Ethylene oligomerization high selectivity catalyst and use thereof

Abstract

The application provides an ethylene oligomerization high-selectivity catalyst and use thereof. The catalyst comprises a phosphine-nitrogen ligand shown in formula I, a transition metal compound and a cocatalyst. Through the ethylene oligomerization reaction of the catalyst system in the application, the overall selectivity of 1-hexene and / or 1-octene can reach more than 90 wt%, and the catalyst has excellent industrialization prospect.

Description

Technical Field

[0001] This invention relates to an ethylene oligomerization catalyst system, and more particularly to a highly selective ethylene oligomerization catalyst and its applications. Background Technology

[0002] Linear α-olefins, also known as straight-chain α-olefins (LAO), generally refer to high-carbon straight-chain terminal olefins with four or more carbon atoms and the general formula RCH=CH2. They are an important class of organic chemical raw materials, used in many fields such as ethylene comonomers, plasticizers, surfactants, and lubricant additives. Among them, α-hexene and 1-octene have seen the most significant market growth. Currently, industrial production of α-olefins is still mainly based on ethylene oligomerization.

[0003] Currently, chromium-based, titanium-based, and tantalum-based catalysts all exhibit good performance in the selective oligomerization of ethylene, with chromium-based catalysts showing superior activity and selectivity, attracting increasing attention from researchers. The performance of these catalysts is primarily influenced by the ligand structure; the steric hindrance and electron-donating effects of the ligands have a significant impact on activity and selectivity. Recent research has focused on ligands with multidentate structures such as PP, PNN, PNP, PNNP, PCCP, SNS, NNZ, and NZN (where Z represents P, N, O, or S atoms). Patents CN103100421A, CN105562090A, CN105562100A, CN107282125A, CN107282132A, CN102451758B, CN101605605, US20100190939A1, US09555404B2, WO / 2012 / 045147, and WO / 2010 / 034102 disclose a series of ethylene tetramerization catalysts with different PNP ligands. Patent US8609924B2 discloses a chromium-based catalyst with a PCCP framework ligand, which exhibits an oligomerization activity of up to 168 kg / gCr. Patent CN101605605A also discloses a method for preparing 1-octene from ethylene tetramerization using a chromium-based catalyst containing a PCCP framework ligand. PCCP exhibits higher oligomerization activity than PNP ligands under the same conditions, but produces a higher polymer yield, which is not conducive to industrialization.

[0004] While maintaining catalytic activity, the product selectivity of PNP catalytic systems is only around 80%, leaving room for improvement. Furthermore, the polymer selectivity of these PNP framework structures is limited by the substituents on nitrogen, generally exceeding 0.2 wt%, which hinders long-term operation of the equipment. Given the current problems of low selectivity and high polymer formation in PNP ligand-structured catalysts, there is an urgent need to develop novel ligand-structured catalysts. Summary of the Invention

[0005] One of the objectives of this invention is to solve the above-mentioned technical problems and provide a highly selective oligomerization catalyst composition for ethylene. The catalyst of this invention exhibits a selectivity of over 90 wt% for 1-hexene and 1-octene, while reducing polymer formation to below 0.05 wt%, demonstrating excellent prospects for industrialization.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A highly selective catalyst composition for ethylene oligomerization, wherein the catalyst comprises a phosphine-nitrogen ligand of formula I, a transition metal compound, and a co-catalyst;

[0008]

[0009] R1, R2, R3, and R4 are each independently selected from one of alkyl, aryl, substituted alkyl, and substituted aryl groups; preferably, R1, R2, R3, and R4 are each independently selected from one of C2-C9 alkyl, aryl, substituted alkyl, and substituted aryl groups; more preferably, R1, R2, R3, and R4 are each independently selected from phenyl, benzyl, biphenyl, naphthyl, anthracene, vinyl, propenyl, isopropyl, tert-butyl, cyclohexyl, 4-methylcyclohexyl, 4-ethylcyclohexyl, 4-isopropylcyclohexyl, 2-methylphenyl, 4-methylphenyl, 2,4-dimethylphenyl, 2,6-dimethylphenyl, 2-ethylphenyl, 4-ethylphenyl, 2,4-diethylphenyl, 2,6-diethylphenyl, and 2-isopropylphenyl. One of 4-isopropylphenyl, 2,4-diisopropylphenyl, 2,6-diisopropylphenyl, 2-butylphenyl, 4-butylphenyl, 2,4-dibutylphenyl, 2,6-dibutylphenyl, 4-methoxyphenyl, o-methoxyphenyl, 4-ethoxyphenyl, o-ethoxyphenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trifluoromethyl)phenyl, 3-(trifluoromethyl)phenyl, 4-(trifluoromethyl)phenyl, 3,5-di(trifluoromethyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl.

[0010] The catalytic active center for ethylene oligomerization is generally a PNP-transition metal-like structure formed by a PNP ligand and a transition metal. The oligomerization mechanism is a cyclic mechanism involving the continuous insertion of ethylene into the metal active center. In the PNNP ligand, nitrogen acts as a substituent on the benzene ring. Due to the lone pair electrons of nitrogen and the conjugation effect of the benzene ring, nitrogen has a certain electron-donating effect, resulting in a larger coordination energy. This reduces the positive charge of the transition metal center, affecting the coordination of ethylene with the transition metal active center, reducing the formation of olefins with C10 or more, and thus increasing the selectivity of 1-hexene and 1-octene in the product.

[0011] In one embodiment of the present invention, the molar ratio of the transition metal compound to the phosphine-nitrogen ligand is 1:(0.9 to 3.5), preferably 1:(1 to 2).

[0012] In one embodiment of the present invention, the molar ratio of the co-catalyst to the transition metal compound is (30-1500):1, preferably (100-900):1.

[0013] In one embodiment of the present invention, the metal element of the transition metal compound is selected from one or more of chromium, molybdenum, cobalt, titanium, vanadium, zirconium, nickel and palladium, preferably one or more of chromium, zirconium and nickel.

[0014] In one embodiment of the present invention, the transition metal compound is in the form of one or more of organic salts, inorganic salts, coordination complexes, and organometallic complexes; preferably, the transition metal compound is one or more of chromium acetylacetone, chromium tri(tetrahydrofuran)trichloride, chromium(III) 2-ethylhexanoate, chromium(III) octanoate, chromium chloride, chromium hexacarbonyl, and chromium (benzene)tricarbonyl.

[0015] In one embodiment of the present invention, the cocatalyst is selected from one or more of alkylaluminum, aluminoxane, and organoboron compounds, preferably one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, diethylaluminum chloride, diethylaluminum chloride, ethylaluminum sesquichloride, methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, propylaluminoxane, butylaluminoxane, isopropylaluminoxane, tert-butylaluminoxane, and organoboron compounds, more preferably methylaluminoxane and / or modified methylaluminoxane.

[0016] Another object of the present invention is to provide a phosphine-nitrogen ligand.

[0017] A phosphine-nitrogen ligand, said ligand being a ligand contained in the above-described catalyst composition, said phosphine-nitrogen ligand having the following structure:

[0018]

[0019] R1, R2, R3, and R4 are each independently selected from one of alkyl, aryl, substituted alkyl, and substituted aryl groups; preferably, R1, R2, R3, and R4 are each independently selected from one of C2-C9 alkyl, aryl, substituted alkyl, and substituted aryl groups; more preferably, R1, R2, R3, and R4 are each independently selected from phenyl, benzyl, biphenyl, naphthyl, anthracene, vinyl, propenyl, isopropyl, tert-butyl, cyclohexyl, 4-methylcyclohexyl, 4-ethylcyclohexyl, 4-isopropylcyclohexyl, 2-methylphenyl, 4-methylphenyl, 2,4-dimethylphenyl, 2,6-dimethylphenyl, 2-ethylphenyl, 4-ethylphenyl, 2,4-diethylphenyl, 2,6-diethylphenyl, and 2-isopropylphenyl. One of 4-isopropylphenyl, 2,4-diisopropylphenyl, 2,6-diisopropylphenyl, 2-butylphenyl, 4-butylphenyl, 2,4-dibutylphenyl, 2,6-dibutylphenyl, 4-methoxyphenyl, o-methoxyphenyl, 4-ethoxyphenyl, o-ethoxyphenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trifluoromethyl)phenyl, 3-(trifluoromethyl)phenyl, 4-(trifluoromethyl)phenyl, 3,5-di(trifluoromethyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl.

[0020] Another object of the present invention is to provide a method for preparing phosphine-nitrogen ligands.

[0021] A method for preparing a phosphine-nitrogen ligand, wherein the ligand is a ligand contained in the above-mentioned catalyst composition, or is a ligand as described above, and the method for preparing the phosphine-nitrogen ligand is as follows:

[0022] After dissolving N1,N3-dimethylphenyl-1,3-diamine, a tertiary aliphatic amine compound was added, followed by the addition of compound of formula II, and the reaction was carried out to obtain the phosphine-nitrogen ligand.

[0023]

[0024] R1, R2, R3, and R4 are each independently selected from one of alkyl, aryl, substituted alkyl, and substituted aryl groups; preferably, R1, R2, R3, and R4 are each independently selected from one of C2-C9 alkyl, aryl, substituted alkyl, and substituted aryl groups; more preferably, R1, R2, R3, and R4 are each independently selected from phenyl, benzyl, biphenyl, naphthyl, anthracene, vinyl, propenyl, isopropyl, tert-butyl, cyclohexyl, 4-methylcyclohexyl, 4-ethylcyclohexyl, 4-isopropylcyclohexyl, 2-methylphenyl, 4-methylphenyl, 2,4-dimethylphenyl, 2,6-dimethylphenyl, 2-ethylphenyl, 4-ethylphenyl, 2,4-diethylphenyl, 2,6-diethylphenyl, and 2-isopropylphenyl. One of 4-isopropylphenyl, 2,4-diisopropylphenyl, 2,6-diisopropylphenyl, 2-butylphenyl, 4-butylphenyl, 2,4-dibutylphenyl, 2,6-dibutylphenyl, 4-methoxyphenyl, o-methoxyphenyl, 4-ethoxyphenyl, o-ethoxyphenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trifluoromethyl)phenyl, 3-(trifluoromethyl)phenyl, 4-(trifluoromethyl)phenyl, 3,5-di(trifluoromethyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl.

[0025] In one embodiment of the present invention, the molar ratio of N1,N3-dimethylbenzene-1,3-diamine, tertiary aliphatic amine compound, and compound of formula II is 1:(1.5-3.5):(2.1-3.6).

[0026] In one embodiment of the present invention, the tertiary fatty amine compound is a C3-C15 tertiary fatty amine compound, preferably triethylamine and / or tripropylamine.

[0027] In one embodiment of the present invention, the dissolution is selected from one or more of halogenated hydrocarbons, nitrile compounds, alkanes, and aromatic solvents, preferably one or more of dichloromethane, acetonitrile, n-hexane, n-heptane, and toluene.

[0028] In one embodiment of the present invention, the preparation method involves reacting at -10 to 30°C for 8 to 30 hours.

[0029] In one embodiment of the present invention, the preparation method is carried out under anhydrous and oxygen-free conditions.

[0030] Another object of the present invention is to provide a use of a catalyst composition.

[0031] Use of a catalyst composition, wherein the composition is the catalyst composition described above, or the catalyst composition of the phosphine-nitrogen ligand described above, or the catalyst composition of the phosphine-nitrogen ligand prepared by the above preparation method, wherein the use is for highly selective catalytic ethylene oligomerization to prepare oligomers, preferably catalytic ethylene oligomerization to prepare 1-hexene and / or 1-octene.

[0032] Another object of the present invention is to provide a method for ethylene oligomerization.

[0033] An ethylene oligomerization method, wherein the method employs the above-described catalyst composition, or a catalyst composition comprising the above-described phosphine-nitrogen ligand, or a catalyst composition comprising a phosphine-nitrogen ligand prepared by the above-described preparation method, the method comprising:

[0034] Solvent and co-catalyst are added to the reactor, along with transition metal compounds and phosphine-nitrogen ligands. After reaching the set reaction temperature, hydrogen and ethylene are introduced to react and prepare oligomer products.

[0035] In one embodiment of the present invention, the reaction temperature in the ethylene oligomerization method is 30–100°C, preferably 40–80°C.

[0036] In one embodiment of the present invention, the gauge pressure of hydrogen gas introduced in the ethylene oligomerization method is 0.1 to 0.9 MPa.

[0037] In one embodiment of the present invention, the gauge pressure of ethylene introduced in the ethylene oligomerization method is 1 to 7 MPa.

[0038] In one embodiment of the present invention, the reaction time in the ethylene oligomerization method is 5 to 240 min, preferably 10 to 100 min.

[0039] Unless otherwise specified, all pressures mentioned in this invention are gauge pressures.

[0040] Compared with the prior art, the positive effects of the oligomerization highly selective catalyst composition of the present invention are as follows:

[0041] The method of the present invention has a total selectivity of more than 90% for ethylene oligomerization of 1-hexene and 1-octene, high atom utilization, reduced production costs, and high economic added value. Detailed Implementation

[0042] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0043] All raw materials used in the examples are conventional in the art, and the purity specifications used are analytical grade or chemically pure. The solvents used in the examples were soaked in molecular sieves to remove water before use.

[0044] Raw material source information:

[0045] N1,N3-Dimethylphenyl-1,3-diamine: 98%, Shanghai Xinkai Pharmaceutical Technology Co., Ltd.

[0046] Triethylamine: ≥99.5% (GC), Shanghai Aladdin Biochemical Technology Co., Ltd.

[0047] Tripropylamine: ≥99.5% (GC), Shanghai Aladdin Biochemical Technology Co., Ltd.

[0048] Diphenylphosphine chloride: 97%, Alfaisa (China) Chemicals Co., Ltd.

[0049] Dichloromethane: 99.5%, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0050] Acetonitrile: 99.5%, Beijing Bailingwei Technology Co., Ltd.

[0051] bis[4-(trifluoromethyl)phenyl]phosphine chloride: 97%, Saen Chemical Technology (China) Co., Ltd.

[0052] Chloro(2-fluorophenyl)(phenyl)phosphine: 97%, Shanghai Xinkai Pharmaceutical Technology Co., Ltd.

[0053] Chloro(3-fluorophenyl)(phenyl)phosphine: 97%, Shanghai Xinkai Pharmaceutical Technology Co., Ltd.

[0054] Chloro(4-fluorophenyl)(phenyl)phosphine: 97%, Shanghai Xinkai Pharmaceutical Technology Co., Ltd.

[0055] bis(4-methylphenyl)phosphine chloride: >97%, Jiangsu Xinnoco Catalyst Co., Ltd.

[0056] bis(2-methoxyphenyl)phosphine chloride: 98%, Alfaesa (China) Chemicals Co., Ltd.

[0057] bis(4-methoxyphenyl)phosphine chloride: 98%, Alfaisa (China) Chemicals Co., Ltd.

[0058] 4-(trimethylsilyl)phenylphosphine chloride: 97%, Jiangsu Xinnoco Catalyst Co., Ltd.

[0059] 4-(tri-n-butylsilyl)phenylphosphine chloride: 97%, Jiangsu Xinnoco Catalyst Co., Ltd.

[0060] Diisopropylphosphine chloride: 98%, Beijing Bailingwei Technology Co., Ltd.

[0061] Ethyl acetate: 99.9%, Bailingwei Technology Co., Ltd.

[0062] Ethanol: Analytical grade, Sinopharm Chemical Reagent Co., Ltd.

[0063] MMAO-3a (Modified Methylaluminoxane): Concentration 7wt% Al, n-Heptane solvent, Nouryon Chemicals (Ningbo) Co., Ltd.

[0064] MAO (methylaluminoxane), 10 wt%, toluene solvent, Nouryon Chemicals (Ningbo) Co., Ltd.

[0065] iPr-PNP (CAS:60981-68-20): >97%, Jiangsu Xinnoco Catalyst Co., Ltd.

[0066] NMR model: BRUKER AVANCE 400, manufacturer: BRUKER AG, Switzerland.

[0067] The catalyst activity of the oligomerization reaction was determined by qualitative and quantitative analysis of the components in the reaction solution. The conditions of the GC analytical instrument used were as follows:

[0068] Instrument Model: Shimadzu GC2010

[0069] Column: DB-5 (30m 0.25mm 0.25μm)

[0070] Column temperature program: First, maintain at 35℃ for 10 min, then increase to 250℃ at a rate of 10℃ / min, and maintain at this temperature for 10 min.

[0071] Detector temperature: 300℃

[0072] Carrier gas: 1 bar

[0073] Air: 0.3 bar

[0074] Gas (H2): 0.3 bar

[0075] Product quality analysis was conducted using the internal standard method.

[0076]

[0077] In the formula, m1 is the mass of a certain product, m is the mass of the internal standard, a1 is the peak area of ​​the product detected in gas chromatography, and a is the peak area of ​​the internal standard. k is a correction coefficient related to the analyte and detection conditions.

[0078] Example 1

[0079] Preparation of phosphine-nitrogen ligands:

[0080] Under anhydrous and oxygen-free conditions, 100 mmol of N1,N3-dimethylbenzene-1,3-diamine was dissolved in 200 mL of dichloromethane. At -5 °C, 220 mmol of triethylamine was added dropwise to the reaction solution with stirring. First, 110 mmol of diphenylphosphine chloride was slowly added. Once the solution stabilized and no further exothermic reaction occurred, another 110 mmol of diphenylphosphine chloride was added. The reaction was stirred for 2 hours, then the cryogenic reaction bath was removed, and the mixture was stirred at room temperature for 15 hours. The reaction solution was purified by column chromatography (eluted with tetrahydrofuran, aspect ratio 2), and then recrystallized at 76 °C (solvent: ethanol:ethyl acetate = 5:1) to obtain the phosphine-nitrogen ligand shown in formula L1:

[0081]

[0082] The NMR data for ligand L1 are as follows: 1 H NMR (400MHz, CDCl3): 7.15-7.42(m,21H), 5.81-6.09(m,3H), 2.78(s,6H).

[0083] Ethylene oligomerization:

[0084] Before the reaction, the 300ml reactor was heated to 150℃ and evacuated for 2 hours, with nitrogen purging three times. After cooling to room temperature, ethylene was purged twice. First, 100ml of dehydrated and deoxygenated solvent methylcyclohexane and 1.2ml of MMAO-3a were added, followed by 4.2μmol of ligand L1 and 3.5μmol of chromium acetylacetone (Al / Cr = 600). Once the temperature was constant at 50℃, 0.5MPa hydrogen and 5.0MPa ethylene were introduced sequentially to initiate the reaction. The reaction temperature was 50℃, and the reaction time was 60min. After the reaction was completed, the ethylene inlet valve was closed, and the reactor was cooled to below 5℃ using an ice-water bath or rapidly. The pressure was slowly released, and the reactor was unloaded to obtain the ethylene oligomer.

[0085] Example 2

[0086] Preparation of phosphine-nitrogen ligands:

[0087] Phosphine-nitrogen ligand L2 was prepared according to the method in Example 1, with the difference being the addition of the following raw materials and the different amounts of each raw material shown in Table 1:

[0088] Replacing triethylamine with tripropylamine and using chloro(2-fluorophenyl)(phenyl)phosphine in the compound shown in Formula II yields the phosphine-nitrogen ligand shown in Formula L2:

[0089]

[0090] The NMR data for ligand L2 are as follows: 1 H NMR (400MHz, CDCl3): 7.13-7.61

[0091] (m,19H), 5.76-6.11(m,3H), 2.72(s,6H).

[0092] Ethylene oligomerization:

[0093] Before the reaction, the 500ml reactor was heated to 140℃ and evacuated for 4 hours, with nitrogen purging three times. After cooling to room temperature, ethylene was purged twice. First, 200ml of dehydrated and deoxygenated solvent methylcyclohexane and 0.80ml of MMAO-3a (7wt% Al, n-heptane) were added, followed by 4.5μmol of ligand L2 and 3.5μmol of tetrahydrofuran chromium chloride (Al / Cr = 400). Once the temperature was constant at 55℃, 0.5MPa hydrogen and 4.5MPa ethylene were introduced sequentially to initiate the reaction. The reaction temperature was 55℃, and the reaction time was 40min. After the reaction was complete, the ethylene inlet valve was closed, and the reactor was cooled to below 5℃ using an ice-water bath or rapidly. The pressure was slowly released, and the reactor was unloaded to obtain the ethylene oligomer.

[0094] Example 3

[0095] Preparation of phosphine-nitrogen ligands:

[0096] Phosphine-nitrogen ligand L3 was prepared according to the method in Example 1, with the difference being the addition of the following raw materials and the different amounts of each raw material shown in Table 1:

[0097] The compound shown in Formula II is selected from chloro(3-fluorophenyl)(phenyl)phosphine to obtain the phosphine-nitrogen ligand shown in Formula L3:

[0098]

[0099] The NMR data for ligand L3 are as follows: 1 H NMR (400MHz, CDCl3): 6.88-7.39

[0100] (m,19H), 5.80~6.12(m,3H), 2.75(s,6H).

[0101] Ethylene oligomerization:

[0102] Before the reaction, the 500ml reactor was heated to 120℃ and evacuated for 2 hours, with nitrogen purging three times. After cooling to room temperature, ethylene was purged twice. First, 200ml of dehydrated and deoxygenated solvent toluene and 1.4ml of MAO were added, followed by 5.0μmol of ligand L3 and 3.5μmol of tetrahydrofuran chromium chloride (Al / Cr = 600). Once the temperature was constant at 60℃, 0.3MPa hydrogen and 4.5MPa ethylene were introduced sequentially to initiate the reaction. The reaction temperature was 60℃, and the reaction time was 40min. After the reaction was complete, the ethylene inlet valve was closed, and the reactor was cooled to below 5℃ using an ice-water bath or rapidly. The pressure was slowly released, and the reactor was unloaded to obtain the ethylene oligomer.

[0103] Example 4

[0104] Preparation of phosphine-nitrogen ligands:

[0105] Phosphine-nitrogen ligand L4 was prepared according to the method in Example 1, with the difference being the addition of the following raw materials and the different amounts of each raw material shown in Table 1:

[0106] Replacing triethylamine with tripropylamine and using chloro(4-fluorophenyl)(phenyl)phosphine in the compound shown in Formula II yields the phosphine-nitrogen ligand shown in Formula L4:

[0107]

[0108] The NMR data for ligand L4 are as follows: 1 H NMR (400MHz, CDCl3): 7.13-7.42 (m, 19H), 5.79-6.07 (m, 3H), 2.82 (s, 6H).

[0109] Ethylene oligomerization:

[0110] Before the reaction, the 500ml reactor was heated to 160℃ and evacuated for 4 hours, with nitrogen purging three times. After cooling to room temperature, ethylene was purged twice. First, 200ml of dehydrated and deoxygenated solvent toluene and 1.0ml of MMAO-3a were added, followed by 5.5μmol of ligand L4 and 3.5μmol of chromium acetylacetone (Al / Cr = 500). Once the temperature was constant at 65℃, 0.4MPa hydrogen and 4.8MPa ethylene were introduced sequentially to initiate the reaction. The reaction temperature was 65℃, and the reaction time was 30min. After the reaction was complete, the ethylene inlet valve was closed, and the reactor was cooled to below 5℃ using an ice-water bath or rapidly. The pressure was slowly released, and the reactor was unloaded to obtain the ethylene oligomer.

[0111] Example 5

[0112] Preparation of phosphine-nitrogen ligands:

[0113] Phosphine-nitrogen ligand L5 was prepared according to the method in Example 1, with the difference being the addition of the following raw materials and the different amounts of each raw material shown in Table 1:

[0114] The compound shown in Formula II was selected from bis[4-(trifluoromethyl)phenyl]phosphine to obtain the phosphine-nitrogen ligand shown in Formula L5:

[0115]

[0116] The NMR data for ligand L5 are as follows: 1 H NMR (400MHz, CDCl3): 7.09-7.47

[0117] (m,17H), 5.75~6.05(m,3H), 2.83(s,6H).

[0118] Ethylene oligomerization:

[0119] Before the reaction, the 500ml reactor was heated to 115℃ and evacuated for 3.5h, with nitrogen purging three times. After cooling to room temperature, ethylene was purged twice. First, 200ml of dehydrated and deoxygenated solvent cyclohexane and 0.6ml of MMAO-3a were added, followed by 4.5μmol of ligand L5 and 3.5μmol of nickel acetylacetone (Al / Ni = 300). Once the temperature was constant at 50℃, 0.5MPa hydrogen and 4.5MPa ethylene were introduced sequentially to initiate the reaction. The reaction temperature was 50℃, and the reaction time was 35min. After the reaction was complete, the ethylene inlet valve was closed, and the reactor was cooled to below 5℃ using an ice-water bath or rapidly. The pressure was slowly released, and the reactor was unloaded to obtain the ethylene oligomer.

[0120] Example 6

[0121] Preparation of phosphine-nitrogen ligands:

[0122] Phosphine-nitrogen ligand L6 was prepared according to the method in Example 1, with the difference being the addition of the following raw materials and the different amounts of each raw material shown in Table 1:

[0123] The compound shown in Formula II is selected from di(4-methylphenyl)phosphine chloride, yielding the phosphine-nitrogen ligand shown in Formula L6:

[0124]

[0125] The NMR data for ligand L6 are as follows: 1 H NMR (400MHz, CDCl3): 7.10-7.16

[0126] (m,17H), 5.85~6.13(m,3H), 2.78(s,6H), 2.37(s,12H).

[0127] Ethylene oligomerization:

[0128] Before the reaction, the 500ml reactor was heated to 115℃ and evacuated for 4 hours, with nitrogen purging three times. After cooling to room temperature, ethylene was purged twice. First, 200ml of dehydrated and deoxygenated solvent methylcyclohexane and 1.6ml of MMAO-3a were added, followed by 7μmol of ligand L6 and 3.5μmol of trichlorotris(tetrahydrofuran)chromium (Al / Cr = 800). Once the temperature was constant at 50℃, 0.5MPa of hydrogen and 4.5MPa of ethylene were introduced sequentially to initiate the reaction. The reaction temperature was 50℃, and the reaction time was 60min. After the reaction was complete, the ethylene inlet valve was closed, and the reactor was cooled to below 5℃ using an ice-water bath or rapidly. The pressure was slowly released, and the reactor was unloaded to obtain the ethylene oligomer.

[0129] Example 7

[0130] Preparation of phosphine-nitrogen ligands:

[0131] Phosphine-nitrogen ligand L7 was prepared according to the method in Example 1, with the difference being the addition of the following raw materials and the different amounts of each raw material shown in Table 1:

[0132] The compound shown in Formula II is selected from bis(2-methoxyphenyl)phosphine chloride, yielding the phosphine-nitrogen ligand shown in Formula L7:

[0133]

[0134] The NMR data for ligand L7 are as follows: 1 H NMR (400MHz, CDCl3): 6.96-7.39

[0135] (m,17H), 5.81~5.99(m,3H), 3.83(s,12H), 2.75(s,6H).

[0136] Ethylene oligomerization:

[0137] Before the reaction, the 300ml reactor was heated to 150℃ and evacuated for 3 hours, with nitrogen purging three times. After cooling to room temperature, ethylene was purged twice. First, 100ml of dehydrated and deoxygenated solvent methylcyclohexane and 1.4ml of MMAO-3a were added, followed by 4.4μmol of ligand L7 and 3.5μmol of zirconium acetylacetonate (Al / Zr = 700). Once the temperature was constant at 50℃, 0.5MPa hydrogen and 4.5MPa ethylene were introduced sequentially to initiate the reaction. The reaction temperature was 50℃, and the reaction time was 55min. After the reaction was completed, the ethylene inlet valve was closed, and the reactor was cooled to below 5℃ using an ice-water bath or rapidly. The pressure was slowly released, and the reactor was unloaded to obtain the ethylene oligomer.

[0138] Example 8

[0139] Preparation of phosphine-nitrogen ligands:

[0140] Phosphine-nitrogen ligand L8 was prepared according to the method in Example 1, with the difference being the addition of the following raw materials and the different amounts of each raw material shown in Table 1:

[0141] The compound shown in Formula II is selected from bis(4-methoxyphenyl)phosphine to obtain the phosphine-nitrogen ligand shown in Formula L8:

[0142]

[0143] The NMR data for ligand L8 are as follows: 1 H NMR (400MHz, CDCl3): 6.95-7.15

[0144] (m,17H), 5.79~6.02(m,3H), 3.81(s,12H), 2.73(s,6H).

[0145] Ethylene oligomerization:

[0146] Before the reaction, the 500ml reactor was heated to 160℃ and evacuated for 2 hours, with nitrogen purging three times. After cooling to room temperature, ethylene was purged twice. First, 200ml of dehydrated and deoxygenated solvent methylcyclohexane and 0.8ml of MMAO-3a were added, followed by 5.5μmol of ligand L8 and 3.5μmol of chromium acetylacetone (Al / Cr = 400). Once the temperature was constant at 45℃, 0.3MPa hydrogen and 4.5MPa ethylene were introduced sequentially to initiate the reaction. The reaction temperature was 45℃, and the reaction time was 45min. After the reaction was complete, the ethylene inlet valve was closed, and the reactor was cooled to below 5℃ using an ice-water bath or rapidly. The pressure was slowly released, and the reactor was unloaded to obtain the ethylene oligomer.

[0147] Example 9

[0148] Preparation of phosphine-nitrogen ligands:

[0149] Phosphine-nitrogen ligand L9 was prepared according to the method in Example 1, with the difference being the addition of the following raw materials and the different amounts of each raw material shown in Table 1:

[0150] The compound shown in Formula II was selected from 4-(trimethylsilyl)phenylphosphine chloride to obtain the phosphine-nitrogen ligand shown in Formula L9:

[0151]

[0152] The NMR data for ligand L9 are as follows: 1 H NMR (400MHz, CDCl3): 7.13-7.40

[0153] (m,17H), 5.79~5.99(m,3H), 2.77(s,6H), 0.27(s,36H).

[0154] Ethylene oligomerization:

[0155] Before the reaction, the 500ml reactor was heated to 120℃ and evacuated for 3 hours, with nitrogen purging three times. After cooling to room temperature, ethylene was purged twice. First, 200ml of dehydrated and deoxygenated solvent methylcyclohexane and 0.8ml of MMAO-3a were added, followed by 6.0μmol of ligand L9 and 3.5μmol of chromium acetylacetone (Al / Cr = 400). Once the temperature was constant at 50℃, 0.5MPa hydrogen and 4.5MPa ethylene were introduced sequentially to initiate the reaction. The reaction temperature was 50℃, and the reaction time was 60min. After the reaction was complete, the ethylene inlet valve was closed, and the reactor was cooled to below 5℃ using an ice-water bath or rapidly. The pressure was slowly released, and the reactor was unloaded to obtain the ethylene oligomer.

[0156] Example 10

[0157] Preparation of phosphine-nitrogen ligands:

[0158] Phosphine-nitrogen ligand L10 was prepared according to the method in Example 1, with the difference being the addition of the following raw materials and the different amounts of each raw material shown in Table 1:

[0159] The compound shown in Formula II was selected from 4-(tri-n-butylsilyl)phenylphosphine chloride to obtain the phosphine-nitrogen ligand shown in Formula L10:

[0160]

[0161] The NMR data for ligand L10 are as follows: 1 H NMR (400MHz, CDCl3): 7.13-7.41 (m, 17H), 5.69~5.98 (m, 3H), 2.69 (s, 6H), 0.89-1.43 (m, 108H).

[0162] Ethylene oligomerization:

[0163] Before the reaction, the 500ml reactor was heated to 160℃ and evacuated for 2 hours, with nitrogen purging three times. After cooling to room temperature, ethylene was purged twice. First, 200ml of dehydrated and deoxygenated solvent methylcyclohexane and 1ml of MMAO-3a were added, followed by 4.1μmol of ligand L10 and 3.5μmol of chromium acetylacetone (Al / Cr = 500). Once the temperature was constant at 50℃, 0.5MPa hydrogen and 4.5MPa ethylene were introduced sequentially to initiate the reaction. The reaction temperature was 50℃, and the reaction time was 60min. After the reaction was complete, the ethylene inlet valve was closed, and the reactor was cooled to below 5℃ using an ice-water bath or rapidly. The pressure was slowly released, and the reactor was unloaded to obtain the ethylene oligomer.

[0164] Example 11

[0165] Preparation of phosphine-nitrogen ligands:

[0166] Phosphine-nitrogen ligand L11 was prepared according to the method in Example 1, with the difference being the addition of the following raw materials and the different amounts of each raw material shown in Table 1:

[0167] The compound shown in Formula II is selected from diisopropylphosphine chloride to obtain the phosphine-nitrogen ligand shown in Formula L11:

[0168]

[0169] The NMR data for ligand L11 are as follows: 1 H NMR (400MHz, CDCl3): 5.79~7.13 (m, 4H), 2.67 (s, 6H), 1.63 (s, 8H), 0.92 (s, 24H).

[0170] Ethylene oligomerization:

[0171] Before the reaction, the 500ml reactor was heated to 160℃ and evacuated for 2 hours, with nitrogen purging three times. After cooling to room temperature, ethylene was purged twice. First, 200ml of dehydrated and deoxygenated solvent methylcyclohexane and 1ml of MMAO were added, followed by 4.1μmol of ligand L11 and 3.5μmol of chromium acetylacetone (Al / Cr = 500). Once the temperature was constant at 50℃, 0.5MPa hydrogen and 4.5MPa ethylene were introduced sequentially to initiate the reaction. The reaction temperature was 50℃, and the reaction time was 60min. After the reaction was complete, the ethylene inlet valve was closed, and the reactor was cooled to below 5℃ using an ice-water bath or rapidly. The pressure was slowly released, and the reactor was unloaded to obtain the ethylene oligomer.

[0172] Comparative Example 1

[0173] The conditions for the ethylene oligomerization experiment were the same as in Example 1, except that the phosphine-nitrogen ligand used was the commercially available catalyst iPr-PNP.

[0174] Table 1. Molar ratio of raw materials and reaction conditions for preparing phosphine-nitrogen ligands in each example.

[0175]

[0176] The products were analyzed by GC, and the catalyst activity and product selectivity in the examples and comparative examples were tested. The results are shown in Table 2.

[0177] Table 2 Catalyst activity and product selectivity in the examples

[0178]

[0179]

[0180] Note: M = Cr, Ni, Zr

[0181] As can be seen from the results in Table 2, the catalytic system using the ligands of this invention can achieve an ethylene oligomerization activity of up to 1300 kg / (gCr·h), a selectivity of over 92 wt% for 1-hexene and 1-octene, and a polymer selectivity as low as 0.05 wt%, all of which are superior to the iPr-PNP ligands reported in the prior art, and have good prospects for industrial application.

[0182] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. An ethylene oligomerization high selectivity catalyst composition characterized in that, The catalyst comprises a phosphine-nitrogen ligand shown in formula I, a transition metal compound, a cocatalyst; Wherein, R1, R2, R3, R4 are each independently selected from one of C2-C9 alkyl, aryl, substituted alkyl, substituted aryl.

2. The catalyst composition of claim 1, wherein, In the catalyst, R1, R2, R3, R4 are each independently selected from one of phenyl, benzyl, biphenyl, naphthyl, anthryl, ethenyl, propenyl, isopropyl, tert-butyl, cyclohexyl, 4-methylcyclohexyl, 4-ethylcyclohexyl, 4-isopropylcyclohexyl, 2-methylphenyl, 4-methylphenyl, 2,4-dimethylphenyl, 2,6-dimethylphenyl, 2-ethylphenyl, 4-ethylphenyl, 2,4-diethylphenyl, 2,6-diethylphenyl, 2-isopropylphenyl, 4-isopropylphenyl, 2,4-diisopropylphenyl, 2,6-diisopropylphenyl, 2-butylphenyl, 4-butylphenyl, 2,4-dibutylphenyl, 2,6-dibutylphenyl, 4-methoxyphenyl, o-methoxyphenyl, 4-ethoxyphenyl, o-ethoxyphenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trifluoromethyl)phenyl, 3-(trifluoromethyl)phenyl, 4-(trifluoromethyl)phenyl, 3,5-di(trifluoromethyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl.

3. The catalyst composition of claim 1, wherein, The molar ratio of the transition metal compound to the phosphine-nitrogen ligand is 1:(0.9-3.5); And / or, the molar ratio of the cocatalyst to the transition metal compound is (30-1500):

1.

4. The catalyst composition of claim 3, wherein, The molar ratio of the transition metal compound to the phosphine-nitrogen ligand is 1:(1-2); And / or, the molar ratio of the cocatalyst to the transition metal compound is (100-900):

1.

5. The catalyst composition of claim 1 or 2, wherein The metal element of the transition metal compound is selected from one or more of chromium, molybdenum, cobalt, titanium, vanadium, zirconium, nickel and palladium; And / or, the compound form of the transition metal compound is one or more of organic salt, inorganic salt, coordination complex.

6. The catalyst composition of claim 5, wherein, The metal element of the transition metal compound is selected from one or more of chromium, zirconium and nickel.

7. The catalyst composition of claim 6, wherein, The transition metal compound is one or more of chromium acetylacetonate, tris(tetrahydrofuran)chromium trichloride, chromium(III) 2-ethylhexanoate, chromium(III) octanoate, chromium chloride, chromium hexacarbonyl, (benzene)tricarbonyl chromium.

8. The catalyst composition of claim 1 or 2, wherein, The cocatalyst is selected from one or more of alkylaluminum, aluminoxane, organoboron compound.

9. The catalyst composition of claim 8, wherein, The cocatalyst is selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, dichlorodiethylaluminum, diethylaluminum chloride, ethylaluminum sesquichloride, methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, propylaluminoxane, butylaluminoxane, isopropylaluminoxane, tert-butylaluminoxane, organoboron compound.

10. The catalyst composition of claim 9, wherein, The cocatalyst is selected from methylaluminoxane and / or modified methylaluminoxane.

11. A phosphine-nitrogen ligand, said ligand being a ligand contained in a catalyst composition according to any one of claims 1 to 10, characterized in that, The phosphine-nitrogen ligand has the following formula structure: R1, R2, R3, R4 are each independently selected from one of C2-C9 alkyl, aryl, substituted alkyl, substituted aryl.

12. The ligand of claim 11, wherein, In the phosphine-nitrogen ligand, R1, R2, R3, R4 are each independently selected from one of phenyl, benzyl, biphenyl, naphthyl, anthryl, ethenyl, propenyl, isopropyl, tert-butyl, cyclohexyl, 4-methylcyclohexyl, 4-ethylcyclohexyl, 4-isopropylcyclohexyl, 2-methylphenyl, 4-methylphenyl, 2,4-dimethylphenyl, 2,6-dimethylphenyl, 2-ethylphenyl, 4-ethylphenyl, 2,4-diethylphenyl, 2,6-diethylphenyl, 2-isopropylphenyl, 4-isopropylphenyl, 2,4-diisopropylphenyl, 2,6-diisopropylphenyl, 2-butylphenyl, 4-butylphenyl, 2,4-dibutylphenyl, 2,6-dibutylphenyl, 4-methoxyphenyl, o-methoxyphenyl, 4-ethoxyphenyl, o-ethoxyphenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trifluoromethyl)phenyl, 3-(trifluoromethyl)phenyl, 4-(trifluoromethyl)phenyl, 3,5-di(trifluoromethyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl.

13. A process for the preparation of a phosphine-nitrogen ligand, said ligand being a ligand contained in a catalyst composition according to any one of claims 1 to 10, or a ligand according to claim 11 or 12, characterized in that, The preparation method of the phosphine-nitrogen ligand is: After dissolving N1, N3-dimethylbenzene-1, 3-diamine, a tertiary aliphatic amine compound is added, and then a compound of formula II is added, and the phosphine-nitrogen ligand is obtained by reaction. R1, R2, R3, R4 are each independently selected from one of C2-C9 alkyl, aryl, substituted alkyl, substituted aryl.

14. The method of claim 13, wherein, In the preparation method of the phosphine-nitrogen ligand, R1, R2, R3, R4 are each independently selected from one of phenyl, benzyl, biphenyl, naphthyl, anthryl, ethenyl, propenyl, isopropyl, tert-butyl, cyclohexyl, 4-methylcyclohexyl, 4-ethylcyclohexyl, 4-isopropylcyclohexyl, 2-methylphenyl, 4-methylphenyl, 2,4-dimethylphenyl, 2,6-dimethylphenyl, 2-ethylphenyl, 4-ethylphenyl, 2,4-diethylphenyl, 2,6-diethylphenyl, 2-isopropylphenyl, 4-isopropylphenyl, 2,4-diisopropylphenyl, 2,6-diisopropylphenyl, 2-butylphenyl, 4-butylphenyl, 2,4-dibutylphenyl, 2,6-dibutylphenyl, 4-methoxyphenyl, o-methoxyphenyl, 4-ethoxyphenyl, o-ethoxyphenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trifluoromethyl)phenyl, 3-(trifluoromethyl)phenyl, 4-(trifluoromethyl)phenyl, 3,5-di(trifluoromethyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl.

15. The preparation method according to claim 13, characterized in that, The molar ratio of the N1,N3-dimethylbenzene-1,3-diamine, the tertiary aliphatic amine compound, and the compound of formula II is 1:(1.5-3.5):(2.1-3.6).

16. The method of claim 13, wherein, The tertiary aliphatic amine compound is a C3-C15 tertiary aliphatic amine compound. The solvent is one or more of a halogenated hydrocarbon, a nitrile compound, an alkane, and an aromatic solvent.

17. The preparation method according to claim 16, characterized in that, The tertiary aliphatic amine compound is triethylamine and / or tripropylamine. The solvent is one or more of dichloromethane, acetonitrile, n-hexane, n-heptane, and toluene.

18. The method of claim 13, wherein, The preparation method is performed at -10-30℃ for 8-30h. The preparation method is performed under anhydrous and anaerobic conditions.

19. Use of a catalyst composition, which composition is a catalyst composition according to any one of claims 1 to 10, or a catalyst composition comprising a phosphine-nitrogen ligand according to claim 11 or 12, or a catalyst composition comprising a phosphine-nitrogen ligand prepared according to the preparation process according to any one of claims 13 to 18, characterized in that, The use is for catalyzing the oligomerization of ethylene to prepare oligomers with high selectivity.

20. Use according to claim 19, characterized in that, The use is for catalyzing the oligomerization of ethylene to prepare 1-hexene and / or 1-octene.

21. A process for the oligomerization of ethylene, characterized in that, The method uses the catalyst composition of any one of claims 1-10, or a catalyst composition comprising the phosphine-nitrogen ligand of claim 11 or 12, or a catalyst composition comprising the phosphine-nitrogen ligand prepared by the preparation method of any one of claims 13-18, and is characterized in that the method is: The reactor is charged with a solvent and a cocatalyst, a transition metal compound, and a phosphine-nitrogen ligand, and after reaching a set reaction temperature, hydrogen and ethylene are introduced to prepare oligomerization products.

22. The method of claim 21, wherein, The reaction temperature in the method is 30-100℃. The hydrogen pressure in the method is 0.1-0.9MPa. The ethylene pressure in the method is 1-7MPa. The reaction time in the method is 5-240min.

23. The method of claim 22, wherein, The reaction temperature in the method is 40-80℃. The reaction time in the method is 10-100min.

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