A sandwich type diimine pyridine iron complex, iron catalyst and preparation method and application thereof

Abstract

The application discloses a sandwich type diimine pyridine iron complex, an iron catalyst and a preparation method and application thereof. The structural formula of the sandwich type diimine pyridine iron complex is shown as formula (I): wherein R is hydrogen, methyl, methoxy or trifluoromethyl. The semi-sandwich diimine pyridine iron catalyst provided by the application can catalyze ethylene polymerization with high activity, and polyethylene wax with an unsaturated double bond at the end can be obtained with high selectivity. The obtained polyethylene wax with an unsaturated double bond at the end can be subjected to in-situ oxidation reaction without separation, and oxidized polyethylene wax can be efficiently prepared. The application can overcome the defects and deficiencies of low efficiency, environmental protection, low efficiency, high energy consumption and uncontrollable product quality caused by the disconnection between catalytic polymerization and oxidation reaction in the preparation process of the existing oxidized polyethylene wax.

Description

Technical Field

[0001] This invention relates to the field of olefin polymerization catalyst technology, and particularly to a sandwich-type diimine pyridine iron complex, an iron catalyst, its preparation method, and its application. Background Technology

[0002] Oxidized polyethylene wax, also known as OPE wax, possesses unique properties such as low viscosity, high softening point, and good hardness. It is non-toxic, has good thermal stability, low high-temperature volatility, and excellent dispersibility for fillers and pigments. It exhibits both excellent external and strong internal lubrication, as well as coupling properties, which can improve the production efficiency of plastics processing and reduce production costs. It also has good compatibility with polyolefin resins. The most important aspect of the modification process for polyethylene wax is the addition of polar groups to the molecular backbone, resulting in an oxidized product with improved physical and chemical properties. Modified polyethylene wax retains some of the properties of the raw material, such as moisture resistance, abrasion resistance, and heat resistance; while also possessing new properties, such as better emulsification, hydrophilicity, and ease of coupling, and compatibility with more polar materials, making it widely used in various industries.

[0003] Oxidized polyethylene wax is mainly obtained by oxidizing and modifying polyethylene wax. Currently, there are three methods for producing polyethylene wax. The first method is the polyethylene pyrolysis method, which uses thermal pyrolysis to break down high molecular weight polyethylene resin into polyethylene wax with a smaller molecular weight. This thermal pyrolysis method requires high energy consumption, and the resulting product has a wide molecular weight distribution. The odor from the low molecular weight is difficult to completely eliminate, and black spots are unavoidable. The second method is to refine oligomers, a byproduct of polyethylene production, to obtain polyethylene wax. This method usually yields a mixture of products with different degrees of polymerization, making it difficult to control quality stability. Furthermore, due to the small molecular weight and complex composition, batch stability is poor, and precipitation is highly likely in end-use applications. The third method is the ethylene synthesis method, which uses ethylene as a raw material to polymerize polyethylene wax with a specific molecular weight under specific conditions; this is also known as synthetic polyethylene wax. Ethylene-synthesized polyethylene wax has high purity, a small molecular weight distribution, stable product quality, and controllable performance, making it suitable for preparing high-quality oxidized polyethylene wax.

[0004] There are two main methods for preparing oxidized polyethylene wax from modified polyethylene wax: one is to directly introduce oxygen-containing gas into the wax melt. This method is more common and has advantages such as low cost and simple process, but it has disadvantages such as high viscosity and a small amount of cross-linking reaction. The other method is to first disperse the wax into fine particles with the help of nonionic emulsifiers at a temperature higher than the melting point of the wax, and then introduce oxygen-containing gas. Under high pressure and the dispersion barrier effect of the aqueous phase, the effects of high viscosity and cross-linking can be avoided. However, the solvent needs to be recovered afterward, which is a complicated process.

[0005] The two current methods for preparing oxidized polyethylene wax are both based on polyethylene wax as raw material. The preparation of polyethylene wax and the preparation of oxidized polyethylene wax are carried out separately, and the preparation processes are completely disconnected, which is not conducive to the requirements of high efficiency, environmental protection and energy saving in chemical production. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects and shortcomings of existing oxidized polyethylene wax preparation processes, such as inefficiency, environmental unfriendliness, low efficiency, high energy consumption, and uncontrollable product quality caused by the disconnect between catalytic polymerization and oxidation reactions. This invention provides a sandwich-type pyridine diimine iron complex and a highly efficient catalyst composed thereof, which can catalyze ethylene polymerization with high activity and high selectivity to obtain polyethylene wax with terminal unsaturated double bonds. The obtained polyethylene wax does not need to be separated and then subjected to in-situ oxidation reaction, thus efficiently preparing oxidized polyethylene wax.

[0007] The purpose of this invention is to provide a sandwich-type diimine pyridine iron complex, the structural formula of which is shown in formula (I):

[0008]

[0009] Wherein, R is hydrogen, methyl, methoxy, or trifluoromethyl.

[0010] In some embodiments of the present invention, R is methyl or methoxy.

[0011] The design principle of the sandwich-type pyridine diimine iron complex provided by this invention is as follows: the sandwich-type pyridine diimine iron complex has a "sandwich" type spatial configuration, which allows for a weak π-π stacking interaction between the axial benzene ring and the pyridine ring in the framework. Furthermore, according to the single-crystal structure data of the complex, the included angle between the benzene ring containing the substituent and the pyridine ring is less than 16°, confirming the existence of a π-π stacking interaction between the benzene ring containing the substituent and the pyridine ring. (See appendix) Figure 1 The weak interaction of this π-π stacking can change and promote the chain transfer mode in the iron-catalyzed ethylene polymerization, and can change the chain transfer mode from transfer to alkylaluminum to β-H elimination, thereby producing polyethylene wax with double bonds at the end with high selectivity.

[0012] Another object of the present invention is to provide a method for preparing the sandwich-type diimine pyridine iron complex, comprising the following steps:

[0013] S1. Substituted aromatic amines and 2,6-diacetylpyridine The reaction yields diimine pyridine.

[0014]

[0015] S2. The diimine pyridine ligand The sandwich-type diimine pyridine iron complex was obtained by reacting with FeCl2.

[0016] In some embodiments of the present invention, in S1, the molar ratio of the 2,6-diacetylpyridine to the substituted aromatic amine is 1:2.1 to 2.4.

[0017] In some embodiments of the present invention, in S2, the molar ratio of the diimine pyridine ligand to FeCl2 is 1.05 to 1.5:1.

[0018] In some embodiments of the present invention, in S2, the molar ratio of the diimine pyridine ligand to FeCl2 is 1.2:1.

[0019] Another object of the present invention is to provide a semi-sandwich diimine pyridine iron catalyst, comprising a main catalyst and a co-catalyst, wherein the main catalyst is the sandwich-type diimine pyridine iron complex.

[0020] In some embodiments of the present invention, the co-catalyst includes at least one of methylaluminoxane (MAO), modified methylaluminoxane (MMAO), and dried methylaluminoxane (dMAO).

[0021] In some embodiments of the present invention, the cocatalyst comprises methylaluminoxane (MAO) or modified methylaluminoxane (MMAO).

[0022] In some embodiments of the present invention, the molar ratio of the main catalyst to the co-catalyst is 1:200 to 2000.

[0023] In some embodiments of the present invention, the molar ratio of the main catalyst to the co-catalyst is 1:1000 to 1500.

[0024] Another object of the present invention is to provide the application of a semi-sandwich diimide pyridine iron catalyst in the catalytic polymerization of ethylene to prepare polyethylene wax.

[0025] In some embodiments of the present invention, the pressure of the ethylene polymerization is 1 to 20 atm.

[0026] In some embodiments of the present invention, the pressure of the ethylene polymerization is 10 to 15 atm.

[0027] In some embodiments of the present invention, the temperature of the ethylene polymerization is 10–80°C.

[0028] In some embodiments of the present invention, the ethylene polymerization time is 15 to 60 minutes.

[0029] In some embodiments of the present invention, the temperature of the ethylene polymerization is 30–50°C.

[0030] In some embodiments of the present invention, the ethylene polymerization time is 30 to 45 minutes.

[0031] In some embodiments of the present invention, the solvent for the polymerization reaction includes at least one of toluene, p-xylene, hexane, cyclohexane, and heptane.

[0032] In some embodiments of the present invention, the solvent for the polymerization reaction is a combination of hexane and cyclohexane.

[0033] Another object of the present invention is to provide the application of a semi-sandwiched diimine pyridine iron catalyst in the preparation of oxidized polyethylene wax.

[0034] In some embodiments of the present invention, the specific steps for preparing oxidized polyethylene wax are as follows: the sandwich-type pyridinediimide iron catalyst catalyzes the polymerization reaction of ethylene to prepare low molecular weight polyethylene wax with unsaturated double bonds at the ends; air is introduced as an oxidant; zinc stearate is added as a catalyst; and oxidized polyethylene wax is obtained in situ.

[0035] In some embodiments of the present invention, the weight-average molecular weight of the oxidized polyethylene wax is 3-8 kg / mol, PDI ≤ 3, and the acid value of the oxidized polyethylene wax is 15-25 mg KOH g. -1 .

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The sandwich-type pyridine diimine iron complex provided by the present invention has a sandwich structure, and the substituted phenyl and pyridine rings have π-π stacking effect, which can selectively prepare polyethylene wax with unsaturated double bonds at the end. The polyethylene wax with double bonds at the end is more easily oxidized to obtain oxidized polyethylene wax with a higher acid value.

[0038] (2) The method for preparing oxidized polyethylene wax provided by the present invention combines catalytic polymerization and in-situ oxidation. The resulting polyethylene wax product does not separate and is further modified by oxidizing by introducing air into the polymerization solution. It has the advantages of high efficiency, environmental protection and energy saving.

[0039] (3) The oxidized polyethylene wax prepared by this invention has high purity, high acid value, and narrow molecular weight distribution (M). w / M n The advantage of ≤3) is that the structure and properties of the product oxidized polyethylene wax can be easily controlled by adjusting the substituents and changing the polymerization conditions.

[0040] (4) This invention utilizes a sandwich-type pyridine diimine iron complex and its metal catalyst to catalyze the polymerization of ethylene, producing polyethylene wax with high purity, narrow molecular weight distribution, and stable quality, terminally unsaturated double bonds. The obtained polyethylene wax product does not separate; it is further oxidized in the polymerization solution by introducing air to obtain oxidized polyethylene wax with a high acidity value. This method organically combines the synthesis of polyethylene wax and the preparation of oxidized polyethylene wax, achieving high efficiency, environmental protection, and energy saving. Simultaneously, the oxidation reaction of polyethylene wax is carried out in solution, resulting in high oxidation efficiency and good product dispersion. It can produce polyethylene wax with high purity, high acid value, and narrow molecular weight distribution (M...). w / M n ≤3) Oxidized polyethylene wax. Attached Figure Description

[0041] Figure 1 This is a single-crystal structure diagram of the sandwich-type pyridine diimine iron complex Fe4 provided in Example 8.

[0042] Figure 2 This is the hydrogen nuclear magnetic spectrum of polyethylene with terminal double bonds provided in Example 15.

[0043] Figure 3 This is the GPC spectrum of the polyethylene wax with terminal double bonds provided in Example 15.

[0044] Figure 4 Here are the chemical structural formulas of the catalysts used in Comparative Examples 1 and 2. Detailed Implementation

[0045] The following will describe the concept and technical effects of the present invention clearly and completely with reference to the embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the embodiments are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0046] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0047] The structural formulas of the sandwich-type diimine pyridine iron complexes in each embodiment are as follows:

[0048]

[0049] In formula (II), the substituent R on the benzene ring is hydrogen, methyl, methoxy or trifluoromethyl.

[0050] Specifically:

[0051] 8-Aryl-1-naphthylamine A1, where R is hydrogen;

[0052] 8-Aryl-1-naphthylamine A2, where R is methyl;

[0053] 8-Aryl-1-naphthylamine A3, where R is a methoxy group;

[0054] 8-Aryl-1-naphthylamine A4, where R is trifluoromethyl;

[0055] Pyridine diimide ligand L1, where R is hydrogen;

[0056] Pyridine diimide ligand L2, where R is a methyl group;

[0057] Pyridine diimide ligand L3, where R is a methoxy group;

[0058] Pyridine diimide ligand L4, where R is trifluoromethyl;

[0059] Sandwich-type pyridinediimide iron complex Fe1, where R is hydrogen;

[0060] Sandwich-type pyridinediimide iron complex Fe2, where R is methyl;

[0061] Sandwich-type pyridinediimide iron complex Fe3, where R is a methoxy group;

[0062] Sandwich-type pyridinediimide iron complex Fe4, where R is trifluoromethyl;

[0063] Sandwich-type diimine pyridine iron complexes were prepared via the following reaction route:

[0064]

[0065] 8-aryl-1-naphthylamines (A1-A4) with different substituents were prepared according to the method reported in the literature (Organometallics 2013, 32(18), 5136-5143).

[0066] In the following examples, the molecular weight and molecular weight distribution of the prepared polyethylene were determined by high-temperature gel permeation chromatography (HT-GPC) using trichlorobenzene as solvent and mobile phase, concentration 1.5 g / L, flow rate 1 mL / min. The selectivity of the polyethylene wax with terminal double bonds was calculated by NMR characterization, and the acid value was determined according to the national standard GB / 264-77.

[0067] Example 1

[0068] This embodiment provides a pyridinediimide unilateral product L1, the synthesis method of which is as follows:

[0069] 2,6-Diacetylpyridine (5.92 mmol), anhydrous methanol (50 mL), and formic acid (0.3 mL) were added sequentially to a 100 mL round-bottom flask and stirred. Then, 8-phenyl-1-naphthylamine A1 (13.03 mmol) dissolved in 5 mL of methanol was slowly added dropwise to the round-bottom flask. The reaction was carried out at room temperature for 8 h. After the reaction was completed, the concentrated system was 20 mL. The solution was filtered, washed with ice-cold methanol, and dried to obtain a yellow solid with a yield of 86%.

[0070] 1 H NMR(CDCl3,ppm): δ7.88(d,2H,H py ),δ7.69(d,2H,H aryl ),δ7.47(m,4H,H aryl ),δ7.39(s,2H,H aryl ),δ7.29(s,1H,H py ),δ7.22(d,6H,H aryl ),δ7.06(t,4H,H aryl ),δ6.84(d,2H,H aryl ),δ6.66(d,2H,H aryl ),δ2.10(s,6H,N=C-CH3).

[0071] 13C NMR(Benzene-d6,ppm); δ164.96,154.81(2C,N=C-CH3),149.30,142.13,140.32,136.09,135.45,134.36,129.58,129 .10,128.57,128.51,128.44,128.32,128.15,126.20,125.41,124.67,124.53,122.58,115.16,16.57(2C,N=C-CH3).

[0072] Example 2

[0073] This embodiment provides a pyridinediimide unilateral product L2, the synthesis method of which is as follows:

[0074] The only difference from Example 1 is that 8-phenyl-1-naphthylamine A1 is replaced with 8-p-tolyl-1-naphthylamine A2, yielding unilateral product L2 in 86% yield.

[0075] 1 H NMR(CDCl3,ppm): δ7.87(d,2H,H py ),δ7.69(d,2H,H aryl ),δ7.47(m,4H,H aryl ),δ7.38(s,2H,H aryl ),δ7.38(s,1H,H py ),δ7.22(d,2H,H aryl ),δ7.10(d,4H,H aryl ),δ6.85(d,4H,H aryl ),δ6.66(d,2H,H aryl ), δ2.10(s,6H,N=C-CH3), δ1.99(s,6H,aryl-CH3).

[0076] 13 C NMR(Benzene-d6,ppm); δ164.96,154.81(2C,N=C-CH3),149.30,142.13,140.32,136.09,135.45,134.36,129.58,129.10,128.5 7,128.51,128.44,128.32,128.15,126.20,125.41,124.67,124.53,122.58,115.16,20.97(2C,aryl-CH3),16.57(2C,N=C-CH3).

[0077] Example 3

[0078] This embodiment provides a pyridinediimide unilateral product L3, the synthesis method of which is as follows:

[0079] The only difference from Example 1 is that 8-phenyl-1-naphthylamine A1 is replaced with 8-p-anisole-1-naphthylamine A3, yielding unilateral product L3 in 88% yield.

[0080] 1 H NMR(CDCl3,ppm): δ7.87(d,2H,H py ),δ7.69(d,2H,H aryl ),δ7.47(m,4H,H aryl ),δ7.38(s,2H,H aryl ),δ7.38(s,1H,H py ),δ7.22(d,2H,H aryl ),δ7.10(d,4H,H aryl ),δ6.67(d,4H,H aryl ),δ6.55(d,2H,H aryl ), δ3.48(s,6H,aryl-O-CH3), δ2.10(s,6H,N=C-CH3).

[0081] 13 C NMR(Benzene-d6,ppm); δ164.90,158.45(1C,N=C-CH3),154.82(1C,N=C-CH3),149.40,140.10,137.27,136.13,134.65,130.14,129.71, 128.45,128.32,128.11,127.95,126.19,125.44,124.80,124.70,122.54,115.04,113.00,54.56(2C,aryl-O-CH3),16.59(2C,N=C-CH3).

[0082] Example 4

[0083] This embodiment provides a pyridinediimide unilateral product L4, the synthesis method of which is as follows:

[0084] The only difference from Example 1 is that 8-phenyl-1-naphthylamine A1 is replaced with 8-p-trifluorotolyl-1-naphthylamine A4, yielding unilateral product L4 in 89% yield.

[0085] 1 H NMR(CDCl3,ppm): δ7.92(d,2H,H py),δ7.71(d,2H,H aryl ),δ7.50(m,4H,H aryl ),δ7.36(s,2H,H aryl ),δ7.36(s,1H,H py ),δ7.31(d,4H,H aryl ),δ7.25(d,6H,H aryl ),δ7.18(d,2H,H aryl ),δ2.06(d,6H,N=C-CH3).

[0086] 13 C NMR(Benzene-d6,ppm); δ165.47,154.34(2C,N=C-CH3),148.82,148.54,138.62,135.92,135.44,129.45,129.29,129.22,128 .57,128.45,128.33,128.12,127.96,126.66,125.24,124.68,124.14,124.11,124.08,122.50,115.31,16.44(2C,N=C-CH3). 19 FNMR (CDCl3, ppm); δ-61.92 (s, 6F, CF3).

[0087] Example 5

[0088] This embodiment provides a sandwich-type pyridinediimine iron complex Fe1, the synthesis method of which is as follows:

[0089] Under anhydrous and oxygen-free conditions, ligand L1 (1.211 mmol) and FeCl2 (1.101 mmol) were added to a Schlenk tube, followed by rapid stirring at room temperature and the addition of 30 mL of freshly distilled THF. The solution immediately turned dark green, and a dark green precipitate slowly formed. After stirring the reaction mixture for 8 h, the system was concentrated under reduced pressure, and the dark green precipitate was precipitated with freshly distilled n-hexane (3 × 10 mL), washed, and dried to obtain the sandwich-type pyridinediimide iron complex Fe1 (dark green powder, 80% yield).

[0090] IR(KBr,cm -1 ):1631(ν C＝N ),1587,1513,1389,1376,1258,1235,1197,838,821,806,779.

[0091] Anal.Calcd for C 41 H 31Cl2FeN3:C,71.19;H,4.49.Found:C,71.12;H,4.51.

[0092] Example 6

[0093] This embodiment provides a sandwich-type pyridinediimide iron complex Fe2, the synthesis method of which is as follows:

[0094] The only difference from Example 5 is that L1 is replaced with L2, resulting in a sandwich-type pyridine diimine iron complex Fe2 with a yield of 82%.

[0095] IR(KBr,cm -1 ):1631(ν C＝N ),1590,1513,1392,1371,1268,1236,1197,838,821,806,779.

[0096] Anal.Calcd for C 43 H 35 Cl2FeN3:C,71.75;H,4.87.Found:C,71.68;H,4.90.

[0097] Example 7

[0098] This embodiment provides a sandwich-type pyridinediimide iron complex Fe3, the synthesis method of which is as follows:

[0099] The only difference from Example 5 is that L1 is replaced with L3, resulting in a sandwich-type pyridine diimine iron complex Fe3 with a yield of 89%.

[0100] IR(KBr,cm -1 ):1610(ν C＝N ),1585,1511,1459,1432,1371,1267,1241,1178,1108,1064

[0101] (ν C -O), 1027,836,809,781.

[0102] Anal.Calcd for C 43 H 35 Cl2FeN3O2:C,68.69;H,4.66.Found:C,68.63;H,4.69.

[0103] Example 8

[0104] This embodiment provides a sandwich-type pyridinediimide iron complex Fe4, the synthesis method of which is as follows.

[0105] The only difference from Example 5 is that L1 is replaced with L4, resulting in a sandwich-type pyridine diimine iron complex Fe4 with a yield of 85%.

[0106] IR(KBr,cm -1 ):1619(ν C＝N ),1587,1504,1428,1373,1324(ν C-F ),1268,1238,1162,1120,1062,1020,836,808,775.

[0107] Anal.Calcd for C 43 H 29 Cl2F6FeN3:C,62.39;H,3.51.Found:C,62.34;H,3.53.

[0108] Example 9

[0109] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe1, the polymerization method of which is as follows:

[0110] The ethylene polymerization reaction was carried out in a 100 mL stainless steel high-temperature and high-pressure reactor equipped with a stirrer. Before polymerization, the reactor was vacuum dried at 200 °C for more than 2 hours. After the reactor cooled to room temperature, freshly distilled toluene solution and MAO (2.4 mmol) solution were sequentially injected through the feed valve. Ethylene gas was introduced to atmospheric pressure, and the reaction system was heated to 50 °C and stirred thoroughly for 10 minutes. A toluene solution of sandwich-type pyridinediimide iron complex Fe1 (2.4 μmol) was added through the feed valve, maintaining the total volume of toluene in the polymerization system at 70 mL. The ethylene pressure was increased to 10 atm and maintained constant throughout the polymerization process. After 30 minutes of polymerization, the ethylene supply was stopped, and the ethylene pressure was slowly released to atmospheric pressure. The reactor was opened, and ethanol was added to terminate the reaction. The product was soaked in hydrochloric acid / ethanol, filtered, washed several times with anhydrous ethanol, and then the polyethylene wax was dried to constant weight in a vacuum drying oven at 60 °C.

[0111] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 98.5.

[0112] Example 10

[0113] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridinediimide iron complex Fe1, the polymerization method of which is as follows:

[0114] The ethylene polymerization reaction was carried out in a 100 mL stainless steel high-temperature and high-pressure reactor equipped with a stirrer. Before polymerization, the reactor was vacuum dried at 200 °C for more than 2 hours. After the reactor cooled to room temperature, freshly distilled toluene solution and MAO (2.4 mmol) solution were sequentially injected through the feed valve. Ethylene gas was introduced to atmospheric pressure, and the reaction system was heated to 50 °C and stirred thoroughly for 10 minutes. A toluene solution of sandwich-type pyridinediimide iron complex Fe1 (2.4 μmol) was added through the feed valve, maintaining the total volume of toluene in the polymerization system at 70 mL. The ethylene pressure was increased to 10 atm and maintained constant throughout the polymerization process. After 30 minutes of polymerization, the ethylene supply was stopped, and the ethylene pressure was slowly released to atmospheric pressure. Then, 0.1 g of zinc stearate was added, and oxygen was introduced to oxidize the product at the reaction temperature for 8 hours. The reactor was then opened, and ethanol was added to terminate the reaction. The product was soaked in hydrochloric acid / ethanol, filtered, washed several times with anhydrous ethanol, and then dried in a vacuum drying oven to constant weight.

[0115] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe1 is 0.91 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 5.0 kg / mol, the molecular weight distribution index (PDI) is 2.4, and the acid value is 20.7 (mg KOH g). -1 ).

[0116] Example 11

[0117] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe2, following the experimental method in Example 9.

[0118] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 97.1.

[0119] Example 12

[0120] This embodiment provides a method for preparing oxidized polyethylene wax by catalytic homopolymerization of ethylene using a sandwich-type pyridine diimine iron complex Fe2, following the experimental method in Example 10.

[0121] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe2 is 1.01 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 5.1 kg / mol, the molecular weight distribution index (PDI) is 1.4, and the acid value is 15.0 mg KOH / g. -1 ).

[0122] Example 13

[0123] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe3, following the experimental method in Example 9.

[0124] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 98.2.

[0125] Example 14

[0126] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by sandwich-type pyridine diimine iron complex Fe3, following the experimental method in Example 10.

[0127] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe3 is 0.82 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 4.5 kg / mol, the molecular weight distribution index (PDI) is 2.3, and the acid value is 19.4 (mg KOH g). -1 ).

[0128] Example 15

[0129] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9.

[0130] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.7.

[0131] Example 16

[0132] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10.

[0133] In this embodiment, the polymerization activity of the sandwich-type pyridine diimide iron complex Fe4 is 2.10 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 5.9 kg / mol, the molecular weight distribution index (PDI) is 2.7, and the acid value is 24.7 (mg KOH g). -1 ).

[0134] Example 17

[0135] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with MMAO as the co-catalyst.

[0136] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 98.4.

[0137] Example 18

[0138] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with MMAO as the co-catalyst.

[0139] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 1.01 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 3.6 kg / mol, the molecular weight distribution index (PDI) is 2.1, and the acid value is 19.7 (mg KOH g). -1 ).

[0140] Example 19

[0141] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with dMAO as the co-catalyst.

[0142] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 97.2.

[0143] Example 20

[0144] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with dMAO as the co-catalyst.

[0145] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 0.52 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 3.0 kg / mol, the molecular weight distribution index (PDI) is 1.3, and the acid value is 15.2 mg KOH / g. -1 ).

[0146] Example 21

[0147] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4. The amount of MAO used is 0.48 mmol, following the experimental method in Example 9.

[0148] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.2%.

[0149] Example 22

[0150] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with an MAO dosage of 0.48 mmol.

[0151] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 0.67 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 7.5 kg / mol, the molecular weight distribution index (PDI) is 3.0, and the acid value is 22.1 (mg KOH g). -1 ).

[0152] Example 23

[0153] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4. The amount of MAO used is 1.2 mmol, following the experimental method in Example 9.

[0154] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.4%.

[0155] Example 24

[0156] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimide iron complex Fe4, following the experimental method in Example 10, with an MAO dosage of 1.2 mmol.

[0157] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 0.83 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 6.5 kg / mol, the molecular weight distribution index (PDI) is 2.9, and the acid value is 23.3 (mg KOH g). -1 ).

[0158] Example 25

[0159] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4. The amount of MAO used is 3.6 mmol, following the experimental method in Example 9.

[0160] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 98.3.

[0161] Example 26

[0162] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4. The amount of MAO used is 3.6 mmol, following the experimental method in Example 10.

[0163] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 1.13 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 3.4 kg / mol, the molecular weight distribution index (PDI) is 1.4, and the acid value is 19.4 (mg KOH g). -1 ).

[0164] Example 27

[0165] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4. The amount of MAO used is 4.8 mmol, following the experimental method in Example 9.

[0166] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 97.4.

[0167] Example 28

[0168] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimide iron complex Fe4. The amount of MAO used is 4.8 mmol, following the experimental method in Example 10.

[0169] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 0.87 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 3.1 kg / mol, the molecular weight distribution index (PDI) is 1.2, and the acid value is 15.1 mg KOH / g. -1 ).

[0170] Example 29

[0171] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe1, following the experimental method in Example 9, with a polymerization temperature of 10°C.

[0172] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 98.3.

[0173] Example 30

[0174] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe1, following the experimental method in Example 10, with a polymerization temperature of 10°C.

[0175] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe1 is 0.02 × 10⁻⁶. 7The weight-average molecular weight of oxidized polyethylene wax is 7.8 kg / mol, the molecular weight distribution index (PDI) is 3.0, and the acid value is 19.4 (mg KOH g). -1 ).

[0176] Example 31

[0177] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe1, following the experimental method in Example 9, with a polymerization temperature of 30°C.

[0178] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 98.5.

[0179] Example 32

[0180] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe1, following the experimental method in Example 10, with a polymerization temperature of 30°C.

[0181] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe1 is 0.47 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 6.2 kg / mol, the molecular weight distribution index (PDI) is 2.9, and the acid value is 20.5 (mg KOH g). -1 ).

[0182] Example 33

[0183] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe1, following the experimental method in Example 9, with a polymerization temperature of 70°C.

[0184] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.4%.

[0185] Example 34

[0186] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe1, following the experimental method in Example 10, with a polymerization temperature of 70°C.

[0187] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe1 is 0.07 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 3.0 kg / mol, the molecular weight distribution index (PDI) is 1.6, and the acid value is 23.5 mg KOH / g. -1 ).

[0188] Example 35

[0189] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe2, following the experimental method in Example 9, with a polymerization temperature of 10°C.

[0190] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 98.3.

[0191] Example 36

[0192] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe2, following the experimental method in Example 10, with a polymerization temperature of 10°C.

[0193] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe2 is 0.12 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 8.0 kg / mol, the molecular weight distribution index (PDI) is 3.0, and the acid value is 19.3 (mg KOH g). -1 ).

[0194] Example 37

[0195] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe2, following the experimental method in Example 9, with a polymerization temperature of 30°C.

[0196] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 98.5.

[0197] Example 38

[0198] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe2, following the experimental method in Example 10, with a polymerization temperature of 30°C.

[0199] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe2 is 0.47 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 6.8 kg / mol, the molecular weight distribution index (PDI) is 2.9, and the acid value is 20.5 (mg KOH g). -1 ).

[0200] Example 39

[0201] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe2, following the experimental method in Example 9, with a polymerization temperature of 70°C.

[0202] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.4%.

[0203] Example 40

[0204] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe2, following the experimental method in Example 10, with a polymerization temperature of 70°C.

[0205] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe2 is 0.17 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 3.0 kg / mol, the molecular weight distribution index (PDI) is 1.6, and the acid value is 22.5 mg KOH / g. -1 ).

[0206] Example 41

[0207] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with a polymerization temperature of 10°C.

[0208] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.3.

[0209] Example 42

[0210] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with a polymerization temperature of 10°C.

[0211] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 0.10 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 8.0 kg / mol, the molecular weight distribution index (PDI) is 3.0, and the acid value is 22.3 (mg KOH g). -1 ).

[0212] Example 43

[0213] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with a polymerization temperature of 20°C.

[0214] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.4%.

[0215] Example 44

[0216] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with a polymerization temperature of 20°C.

[0217] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 0.97 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 7.8 kg / mol, the molecular weight distribution index (PDI) is 3.0, and the acid value is 22.5 mg KOH / g. -1 ).

[0218] Example 45

[0219] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with a polymerization temperature of 30°C.

[0220] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.5.

[0221] Example 46

[0222] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with a polymerization temperature of 30°C.

[0223] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 1.47 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 7.5 kg / mol, the molecular weight distribution index (PDI) is 2.9, and the acid value is 23.0 mg KOH / g. -1 ).

[0224] Example 47

[0225] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with a polymerization temperature of 40°C.

[0226] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.6.

[0227] Example 48

[0228] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with a polymerization temperature of 40°C.

[0229] In this embodiment, the polymerization activity of the sandwich-type pyridine diimide iron complex Fe4 is 1.60 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 6.2 kg / mol, the molecular weight distribution index (PDI) is 2.8, and the acid value is 23.7 (mg KOH g). -1 ).

[0230] Example 49

[0231] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with a polymerization temperature of 60°C.

[0232] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.7.

[0233] Example 50

[0234] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with a polymerization temperature of 60°C.

[0235] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 1.37 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 4.6 kg / mol, the molecular weight distribution index (PDI) is 2.7, and the acid value is 24.7 (mg KOH g). -1 ).

[0236] Example 51

[0237] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with a polymerization temperature of 70°C.

[0238] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.8%.

[0239] Example 52

[0240] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with a polymerization temperature of 70°C.

[0241] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 1.07 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 3.7 kg / mol, the molecular weight distribution index (PDI) is 2.5, and the acid value is 24.9 (mg KOH g). -1 ).

[0242] Example 53

[0243] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with a polymerization temperature of 80°C.

[0244] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.8%.

[0245] Example 54

[0246] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with a polymerization temperature of 80°C.

[0247] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 0.80 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 3.0 kg / mol, the molecular weight distribution index (PDI) is 2.1, and the acid value is 25.0 mg KOH / g. -1 ).

[0248] Example 55

[0249] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with an ethylene pressure of 1 atm.

[0250] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 98.8.

[0251] Example 56

[0252] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with an ethylene pressure of 1 atm.

[0253] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 0.03 × 10⁻⁶. 7The weight-average molecular weight of oxidized polyethylene wax is 3.6 kg / mol, the molecular weight distribution index (PDI) is 1.3, and the acid value is 21.4 (mg KOH g). -1 ).

[0254] Example 57

[0255] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimide iron complex Fe4, following the experimental method in Example 9, with an ethylene pressure of 5 atm.

[0256] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.0.

[0257] Example 58

[0258] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with an ethylene pressure of 5 atm.

[0259] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 0.58 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 4.3 kg / mol, the molecular weight distribution index (PDI) is 1.4, and the acid value is 22.0 mg KOH / g. -1 ).

[0260] Example 59

[0261] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with an ethylene pressure of 15 atm.

[0262] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.3.

[0263] Example 60

[0264] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with an ethylene pressure of 15 atm.

[0265] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 2.52 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 6.4 kg / mol, the molecular weight distribution index (PDI) is 1.9, and the acid value is 22.3 mg KOH / g. -1 ).

[0266] Example 61

[0267] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with an ethylene pressure of 20 atm.

[0268] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.2%.

[0269] Example 62

[0270] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with an ethylene pressure of 20 atm.

[0271] In this embodiment, the polymerization activity of the sandwich-type pyridine diimide iron complex Fe4 is 2.05 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 7.3 kg / mol, the molecular weight distribution index (PDI) is 2.5, and the acid value is 21.9 (mg KOH g). -1 ).

[0272] Example 63

[0273] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with p-xylene as the solvent.

[0274] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.2%.

[0275] Example 64

[0276] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with p-xylene as the solvent.

[0277] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 1.84 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 6.4 kg / mol, the molecular weight distribution index (PDI) is 1.6, and the acid value is 21.9 (mg KOH g). -1 ).

[0278] Example 65

[0279] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with hexane as the solvent.

[0280] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.4%.

[0281] Example 66

[0282] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with hexane as the solvent.

[0283] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 2.41 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 7.2 kg / mol, the molecular weight distribution index (PDI) is 1.1, and the acid value is 23.4 (mg KOH g). -1 ).

[0284] Example 67

[0285] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, using cyclohexane as the solvent, following the experimental method in Example 9.

[0286] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.8%.

[0287] Example 68

[0288] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with cyclohexane as the solvent.

[0289] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 2.45 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 6.3 kg / mol, the molecular weight distribution index (PDI) is 1.3, and the acid value is 25.0 mg KOH / g. -1 ).

[0290] Example 69

[0291] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with heptane as the solvent.

[0292] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.3.

[0293] Example 70

[0294] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with heptane as the solvent.

[0295] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 2.01 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 3.4 kg / mol, the molecular weight distribution index (PDI) is 1.5, and the acid value is 22.3 mg KOH / g. -1 ).

[0296] Example 71

[0297] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with a polymerization time of 15 min.

[0298] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.7.

[0299] Example 72

[0300] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with a polymerization time of 15 min.

[0301] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 1.01 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 3.4 kg / mol, the molecular weight distribution index (PDI) is 1.3, and the acid value is 24.6 mg KOH / g. -1 ).

[0302] Example 73

[0303] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with a polymerization time of 45 min.

[0304] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.4%.

[0305] Example 74

[0306] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with a polymerization time of 45 min.

[0307] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 1.85 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 6.8 kg / mol, the molecular weight distribution index (PDI) is 2.1, and the acid value is 23.8 (mg KOH g). -1 ).

[0308] Example 75

[0309] This embodiment provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 9, with a polymerization time of 60 min.

[0310] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 99.0.

[0311] Example 76

[0312] This embodiment provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by a sandwich-type pyridine diimine iron complex Fe4, following the experimental method in Example 10, with a polymerization time of 60 min.

[0313] In this embodiment, the polymerization activity of the sandwich-type pyridinediimide iron complex Fe4 is 1.23 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 7.3 kg / mol, the molecular weight distribution index (PDI) is 2.8, and the acid value is 23.0 mg KOH / g. -1 ).

[0314] Comparative Example 1

[0315] This comparative example provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by pyridine diimine iron complex Fe5, following the experimental method in Example 9.

[0316] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 9.0.

[0317] Comparative Example 2

[0318] This comparative example provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by pyridine diimine iron complex Fe5, following the experimental method in Example 10.

[0319] In this comparative example, the polymerization activity of the pyridine diimine iron complex Fe5 was 1.65 × 10⁻⁶.7 The weight-average molecular weight of oxidized polyethylene wax is 35.7 kg / mol, the molecular weight distribution index (PDI) is 2.7, and the acid value is 0.9 (mg KOH g). -1 ).

[0320] Comparative Example 3

[0321] This comparative example provides a method for preparing polyethylene wax by homopolymerization of ethylene catalyzed by pyridine diimine iron complex Fe5, following the experimental method in Example 9, with a polymerization temperature of 70°C.

[0322] In this embodiment, the double bond molar percentage α (mol%) of the polyethylene wax is 13.7.

[0323] Comparative Example 4

[0324] This comparative example provides a method for preparing oxidized polyethylene wax by homopolymerization of ethylene catalyzed by pyridine diimine iron complex Fe5, following the experimental method in Example 10, with a polymerization temperature of 70°C.

[0325] In this comparative example, the polymerization activity of the pyridine diimine iron complex Fe5 was 0.73 × 10⁻⁶. 7 The weight-average molecular weight of oxidized polyethylene wax is 27.5 kg / mol, the molecular weight distribution index (PDI) is 2.1, and the acid value is 1.2 (mg KOH g). -1 ).

[0326] By comparing the examples and comparative examples, it can be clearly found that the sandwich-type pyridine diimine iron complex Fe1-4 is better than the pyridine diimine iron complex Fe5 in terms of selectivity, catalytic activity, product distribution, and subsequent oxidation degree of polyethylene wax with terminal double bonds. This indicates that the sandwich structure of the sandwich-type pyridine diimine iron complex Fe1-4, which introduces weak π-π stacking interactions, is a very feasible design scheme for catalyzing the polymerization-oxidation of ethylene to prepare high-quality oxidized polyethylene wax.

[0327] As described above, the sandwich-type pyridinediimide iron complex provided by this invention can serve as a main catalyst. With the aid of a specific co-catalyst, it catalyzes the polymerization-oxidation of ethylene with high activity under relatively low ethylene pressure to obtain oxidized polyethylene wax with a high acid value. The entire reaction is conducted under mild conditions, exhibiting high catalytic activity, low ethylene monomer prices, a simple production process, easy product separation, and low production costs. The resulting oxidized polyethylene wax has a relatively narrow distribution, high acid value, stable performance, and good lubricity, making it suitable for use as a high-quality oxidized polyethylene wax.

[0328] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A sandwich-type diimine pyridine iron complex, characterized in that, The structural formula of the sandwich-type diimine pyridine iron complex is shown in formula (I): Equation (I); Wherein, R is hydrogen, methyl, methoxy, or trifluoromethyl.

2. The method for preparing the sandwich-type diimine pyridine iron complex according to claim 1, characterized in that, Includes the following steps: S1. Substituted aromatic amines and 2,6-diacetylpyridine The reaction yields diimine pyridine. ; S2. The diimine pyridine The sandwich-type diimine pyridine iron complex was obtained by reacting with FeCl2. .

3. A sandwich-type diimine pyridine iron catalyst, characterized in that, It includes a main catalyst and a co-catalyst, wherein the main catalyst is the sandwich-type diimine pyridine iron complex as described in claim 1.

4. The sandwich-type diimine pyridine iron catalyst according to claim 3, characterized in that, The co-catalyst includes at least one of methylaluminoxane (MAO), modified methylaluminoxane (MMAO), and dried methylaluminoxane (dMAO).

5. The sandwich-type diimine pyridine iron catalyst according to claim 4, characterized in that, The molar ratio of the main catalyst to the co-catalyst is 1:200~2000.

6. The application of the sandwich-type diimine pyridine iron catalyst according to any one of claims 3 to 5 in the catalytic polymerization of ethylene to prepare polyethylene wax.

7. The application according to claim 6, characterized in that, The pressure for the ethylene polymerization is 1~20 atm; And / or, the temperature for the ethylene polymerization is 10~80°C; And / or, the ethylene polymerization time is 15~60 min.

8. The application according to claim 6, characterized in that, The solvent used for polymerization includes at least one of toluene, p-xylene, hexane, cyclohexane, and heptane.

9. The use of the sandwich-type diimine pyridine iron catalyst according to any one of claims 3 to 5 in the preparation of oxidized polyethylene wax.

10. The application according to claim 9, characterized in that, The oxidized polyethylene wax has a weight-average molecular weight of 3-8 kg / mol, a PDI ≤ 3, and an acid value of 15-25 mg KOH g. -1 .

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