A catalyst combination and a method for producing poly-alpha-olefin synthetic oil using the same

Abstract

The application provides a catalyst combination and a method for preparing poly-alpha-olefin synthetic oil by using the catalyst combination. The catalyst combination comprises a phosphorus-nitrogen ligand-chromium salt complex, a metallocene catalyst and / or a post-metallocene catalyst, and a cocatalyst. The preparation method adopts a double-kettle series process, and uses ethylene as a single raw material. High-carbon alpha-olefins are prepared in a first reaction kettle, and then the reaction liquid is transferred to a second reaction kettle for continuous reaction to prepare synthetic oil. The application uses low-price ethylene as a main raw material, can reduce the use of imported high-carbon alpha-olefins, has lower raw material cost, and has a wide viscosity range and excellent product performance, and has a good market application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of synthetic lubricating oil base oil, and particularly relates to a catalyst combination and a method for preparing poly-alpha-olefin synthetic oil by using the catalyst combination. BACKGROUND

[0002] Lubricating oil base oil is generally divided into mineral base oil and synthetic base oil. Mineral base oil is mainly obtained by taking crude oil as raw material, and through processes such as atmospheric and vacuum distillation, solvent refining, solvent dewaxing, solvent deasphalting, and then through different production processes such as desulfurization and hydrogenation. With the increasing demand for lubricating oil in industry, mineral base oil cannot meet the industrial demand in many harsh conditions, and synthetic base oil is getting more and more attention due to its excellent performance. Synthetic base oil is a kind of lubricating oil base oil with special performance and chemical structure, which is mainly prepared by chemical synthesis method. Common ones are synthetic hydrocarbon, polyether, silicone oil, synthetic ester, phosphate ester, etc. Among them, the most widely used is poly-alpha-olefin synthetic oil (PAO).

[0003] PAO is mainly long-chain alkanes obtained by polymerization of C8-C12 alpha-olefins under the action of a catalyst, and then refined by alkaline, water washing, hydrogenation, etc. PAO base oil has obvious advantages in viscosity-temperature characteristics, low-temperature fluidity, additives, thermal oxidation stability, etc. Unfortunately, there is still no mature industrialized device for producing PAO in China at present, and the high-carbon alpha-olefins for synthesizing PAO are all dependent on imports. The mainstream production process of PAO mostly uses Lewis acid catalysts such as BF3 or AlCl3, but generally only produces medium and low viscosity products with incomplete side chains. In 2010, ExxonMobil launched a new generation of PAO synthetic oil based on metallocene catalyst technology, which has higher polymerization activity and can produce mPAO with regular comb structure and uniform polymerization degree. At present, only ExxonMobil, Chevron, Ineos, Lyondell and Japan's Showa can produce high-viscosity mPAO products of 40-300 cSt, but the technology is not transferred to others.

[0004] At present, there is a lack of high-quality high-carbon alpha-olefins for polymerization in China, and only 1-hexene can be produced, and C8 and other alpha-olefins are all supplied by foreign markets. Research institutions such as Northeast Petroleum University, Tianjin University of Science and Technology, Shanghai Institute of Higher Learning, etc. have carried out a series of researches on the synthesis of PAO, using different metallocene catalysts, and the small-scale experimental products have made some progress, but there is still a long way to go for industrial production. In summary, the raw material high-carbon alpha-olefin required in the existing PAO synthesis method is expensive and all depends on imports, and the prepared PAO product is difficult to balance low-temperature fluidity and viscosity-temperature performance. SUMMARY

[0005] In view of the dependence of existing processes for preparing polyalphaolefin synthetic oil on imported high-carbon alpha-olefins, the present invention aims to provide a catalyst composition for preparing polyalphaolefin synthetic oil. The catalyst composition significantly reduces the raw material cost for preparing polyalphaolefin synthetic oil, and the synthesized PAO has excellent low-temperature fluidity and viscosity-temperature properties.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] A catalyst composition for preparing polyalphaolefin synthetic oil, the catalyst composition comprising a phosphine nitrogen ligand-chromium salt complex, a metallocene catalyst and / or a post-metallocene catalyst, and a co-catalyst.

[0008] In this invention, the structure of the phosphine nitrogen ligand-chromium salt complex is shown in Formula I:

[0009] R1, R2, R3, and R4 are each independently selected from vinyl, propenyl, cyclohexyl, and silane-containing aromatic compounds.

[0010]

[0011] one or more of phenyl, benzyl, biphenyl, naphthyl, anthryl, ethenyl, propenyl, 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-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl, more preferably one or more of 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-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl; R5, R6, R7are each independently selected from one or more of hydrogen, alkyl, alkoxy, preferably one or more of hydrogen, methyl, ethyl, methoxy, ethoxy, isopropoxy, cyclopropyl.

[0012] In the present invention, the metallocene catalyst and / or post-metallocene catalyst is selected from one or more of titanium, zirconium, hafnium based catalysts, preferably one or more of dimethylsilyl(N-tert-butylamido)(tetramethylcyclopentadienyl) titanium dichloride, dimethylsilyl(N-tert-butylamido)(tetramethylcyclopentadienyl) titanium dimethyl, dimethylsilyl(N-tert-butylamido)(fluorenyl) titanium dichloride, (pentamethylcyclopentadienyl) titanium trimethoxide, dimethylsilyl bis(propylcyclopentadienyl) hafnium dichloride, bis(n-butylcyclopentadienyl) hafnium dichloride, racemic dimethylsilyl bis(2-methyl-1-indenyl) zirconium dichloride, benzylidene cyclopentadienyl (2,7-di-tert-butyl-fluorenyl) zirconium dichloride, di-p-tolylidene cyclopentadienyl (2,7-di-tert-butyl-fluorenyl) zirconium dichloride, benzylidene (cyclopentadienyl)(9-fluorenyl) zirconium dichloride, dimethylsilyl bis(2-methyl-4-phenyl-1-indenyl) zirconium dichloride), meso dimethylsilyl bis(1-indenyl) zirconium dichloride, (bis(methylcyclopentadienyl) zirconium dichloride), (bis(1,3-dimethylcyclopentadienyl) zirconium dichloride, (cyclopentadienyl)(1,2-dimethoxyethane) zirconium trichloride, diphenylsilyl (cyclopentadienyl)(9-fluorenyl) zirconium dichloride.

[0013] In the present invention, the co-catalyst is selected from one or more of organoaluminum compounds and / or organoboron compounds; preferably, the organoaluminum compound is selected from one or more of alkyl aluminum, chlorinated alkyl aluminum, alkyl aluminoxane, preferably one or more of trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, diethyl ethoxy aluminum, monochlorodiethyl aluminum, dichloroethyl aluminum, sesquiethyl aluminum chloride, trioctyl aluminum, methyl aluminoxane (MAO), modified methyl aluminoxane (MMAO), or ethyl aluminoxane; preferably, the organoboron compound is selected from one or more of boron oxane, alkyl boron, borate, borate ester, preferably one or more of boron oxane, triethyl borane, triphenyl borane, triphenyl borane ammine complex, NaBH4, tributyl borate, triisopropyl borate, tris(pentafluorophenyl)borane, triphenylcarbenium tetrakis(pentafluorophenyl)borate, tri(p-n-octylphenyl)carbenium tetrakis(pentafluorophenyl)borate, dimethylphenylammonium tetrakis(pentafluorophenyl)borate, diethylphenylammonium tetrakis(pentafluorophenyl)borate, methyldiphenylammonium tetrakis(pentafluorophenyl)borate, ethyldiphenylammonium tetrakis(pentafluorophenyl)borate, methyldioctadecylammonium tetrakis(pentafluorophenyl)borate, trioctylammonium tetrakis(pentafluorophenyl)borate.

[0014] In the present invention, the molar ratio of the co-catalyst to phosphine nitrogen ligand-chromium salt complex is 50-2000:1, preferably 100-1000:1; the molar ratio of the co-catalyst to metallocene catalyst and / or post-metallocene catalyst is 0.8-1000:1, preferably 1-700:1.

[0015] The metallocene catalyst in the application belongs to a single active center catalyst, and the polymerization product has good uniformity and narrow relative molecular weight distribution. In the synergistic effect of the alkylaluminoxane cocatalyst, more stable cationic active centers can be obtained, the polymerization activity is higher, and PAO with regular comb structure and uniform polymerization degree can be produced.

[0016] Another object of the application is to provide a use of the catalyst composition.

[0017] A use of the catalyst composition described above for preparing poly-alpha-olefin synthetic oil.

[0018] Still another object of the application is to provide a method for preparing poly-alpha-olefin synthetic oil.

[0019] A method for preparing poly-alpha-olefin synthetic oil, which adopts the catalyst composition described above, and in the presence of the catalyst composition, ethylene is first polymerized into high-carbon alpha-olefin and then polymerized to prepare poly-alpha-olefin synthetic oil.

[0020] In the application, the method adopts a double-kettle series process; preferably, the method comprises the following steps:

[0021] S1: adding a solvent, a phosphine-nitrogen ligand-chromium salt complex and a cocatalyst into a first reaction kettle, and reacting to prepare alpha-olefin;

[0022] S2: transferring the reaction liquid to a second reaction kettle, adding a metal catalyst and / or a post-metallocene catalyst, a cocatalyst, continuing the reaction, terminating the reaction, cooling, and obtaining the product.

[0023] In the application, the S1 reaction temperature is 35-80℃, and the gauge pressure is 2-6MPa.

[0024] In the application, the reaction liquid is transferred to the second reaction kettle after 15min-60min of the S1 reaction.

[0025] In the application, the solvent in S1 is one or more of benzene compounds, alkanes and cycloalkanes, and preferably one or more of toluene, methylcyclohexane, cyclohexane, n-heptane, n-octane, n-butane, isobutane, n-pentane, cyclopentane, methylcyclopentane, methylene cyclopentane, benzene and xylene.

[0026] In the application, the S2 reaction temperature is 100-160℃, and the gauge pressure is 0.05-1MPa.

[0027] In the application, the S2 reaction is terminated after 30-70min of the reaction.

[0028] Still another object of the application is to provide a poly-alpha-olefin synthetic oil.

[0029] A polyalphaolefin synthetic oil prepared using the catalyst composition described above, or prepared using the method of preparing a polyalphaolefin synthetic oil described above, said synthetic oil having a viscosity index VI > 120, and a pour point < -45°C.

[0030] It is a further object of the present invention to provide a phosphinonitrogen ligand-chromium salt complex.

[0031] A phosphinonitrogen ligand-chromium salt complex, said complex being the complex contained in the catalyst composition described above, said complex having the structure of Formula I:

[0032]

[0033] wherein R1, R2, R3, R4 are each independently selected from one or more of vinyl, propenyl, cyclohexyl, silane-containing aryl, alkyl-containing aryl, alkoxy-containing aryl, fluorine-containing alkyl, preferably one or more of phenyl, benzyl, biphenyl, naphthyl, anthryl, vinyl, propenyl, 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-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl, more preferably one or more of 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-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl; R5, R6, R7 are each independently selected from one or more of hydrogen, alkyl, alkoxy, preferably one or more of hydrogen, methyl, ethyl, methoxy, ethoxy, isopropoxy, cyclopropyl.

[0034] In the present application, the phosphine-nitrogen ligand-chromium salt complex is prepared from the phosphine-nitrogen ligand and chromium chloride tetrahydrofuran in a solvent, and after a blue powder-like precipitate is formed, the solvent is cooled, filtered, washed and dried to obtain the phosphine-nitrogen ligand-chromium salt complex I.

[0035] In the present application, the mass ratio of the chromium chloride tetrahydrofuran to the phosphine-nitrogen ligand is 1:1-1.2, the reaction temperature is 70-120°C, and the stirring time is 7-15h.

[0036] A further object of the present application is to provide a phosphine-nitrogen ligand.

[0037] A phosphazene ligand, which is a ligand of the complex in the above-mentioned catalyst composition, or which is a ligand of the above-mentioned phosphazene ligand-chromium salt complex, the structure of the ligand being shown in Formula II:

[0038]

[0039] wherein R1, R2, R3, R4are each independently selected from one or more of vinyl, propenyl, cyclohexyl, silane-containing aryl, alkyl-containing aryl, alkoxy-containing aryl, fluoro-containing alkyl, preferably one or more of phenyl, benzyl, biphenyl, naphthyl, anthryl, vinyl, propenyl, 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-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl, more preferably one or more of 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-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl; R5, R6, R7are each independently selected from one or more of hydrogen, alkyl, alkoxy, preferably one or more of hydrogen, methyl, ethyl, methoxy, ethoxy, isopropoxy, cyclopropyl.

[0040] It is still another object of the present application to provide a method for preparing the above-mentioned phosphazene ligand.

[0041] A process for the preparation of the above phosphorus-nitrogen ligand, the steps of which are: addition of a tertiary aliphatic amine compound, preferably a C3-C15 tertiary aliphatic amine compound, more preferably triethylamine and / or tripropylamine, to provide a basic environment, to a solution of a compound of formula III, neutralization of the substituted Cl, addition of a compound of formula IV, stirring of the reaction, purification to obtain the phosphorus-nitrogen ligand:

[0042]

[0043] wherein R5, R6, R7 are each independently selected from one or more of hydrogen, alkyl, alkoxy, preferably one or more of hydrogen, methyl, ethyl, methoxy, ethoxy, isopropoxy, cyclopropyl;

[0044]

[0045] wherein R1, R2 are each independently selected from one or more of vinyl, propenyl, cyclohexyl, silane-containing aryl, alkyl-containing aryl, alkoxy-containing aryl, fluorine-containing alkyl, preferably one or more of phenyl, benzyl, biphenyl, naphthyl, anthryl, vinyl, propenyl, 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-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl, more preferably one or more of 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-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, 4-(tri-n-butylsilyl)phenyl.

[0046] Compared with the prior art, the positive effects of the present application are:

[0047] (1) The catalyst has high activity, and the viscosity of the poly-alpha-olefin synthetic oil prepared by the double-kettle series process is controllable, the product has a narrow molecular weight distribution, and has excellent performance.

[0048] (2) Ethylene is used as a single raw material, avoiding the use of expensive high-carbon a-olefin raw materials, and the economic advantage is outstanding. DETAILED DESCRIPTION

[0049] The following specific examples only illustrate the present application, but these examples are only part of the present application, and do not limit the application in other fields. The raw materials used in the examples are all conventional raw materials in the art, and the purity specifications used are analytical or chemical pure. The pressures involved are all gauge pressures.

[0050] Raw material source information:

[0051] 2-aminopyrimidine: 99%, Bailingwei Technology Co., Ltd.

[0052] 5-cyclopropylpyrimidin-2-amine: 97%, Shanghai Bide Pharmaceutical Technology Co., Ltd.

[0053] 4,5-dimethoxypyrimidin-2-amine: 97%, Shanghai Bide Pharmaceutical Technology Co., Ltd.

[0054] 4-isopropoxypyrimidin-2-amine: 97%, Shanghai Bide Pharmaceutical Technology Co., Ltd.

[0055] Triethylamine, tripropylamine: ≥99.5% (GC), Shanghai Aladdin Bio-Chem Technology Co., Ltd.

[0056] Diphenylchlorophosphine: 97%, Alfa Aesar (China) Chemicals Co., Ltd.

[0057] Di(4-methylphenyl)chlorophosphine: 98%, Alfa Aesar (China) Chemicals Co., Ltd.

[0058] Chloro(4-fluorophenyl)(phenyl)phosphine: 97%, Shanghai Xikai Pharmaceutical Technology Co., Ltd.; 4-(Tri-n-butylsilyl)phenylchlorophosphine: 97%, Jiangsu Xinnuo Catalyst Co., Ltd.

[0059] Ethyl acetate: 99.9%, Bailingwei Technology Co., Ltd.

[0060] Ethanol: analytical pure, National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0061] MMAO-3a (modified methylaluminoxane): concentration 7wt% Al, n-heptane solvent, Norell Chemicals (Ningbo) Co., Ltd.

[0062] MMAO-7 (modified methylaluminoxane): concentration 7wt% Al, Isopar E solvent, Norell Chemicals (Ningbo) Co., Ltd.

[0063] MAO (methylaluminoxane), concentration 10wt%, toluene solvent, Norell Chemicals (Ningbo) Co., Ltd.

[0064] The analysis method applied in this embodiment is as follows:

[0065] The kinematic viscosity of the polyolefin synthetic oil was measured according to GB 265 Petroleum Products - Determination of kinematic viscosity and calculation of dynamic viscosity.

[0066] The viscosity index was calculated according to GB 2541 Petroleum Products - Calculation of Viscosity Index.

[0067] The pour point was measured according to GB 3535 Petroleum Products - Determination of pour point.

[0068] The kinematic viscosity tester was Model SYD-265C, made by Shanghai Geological Instrument Factory.

[0069] The pour point tester was Model HM-NQ, made by Shandong Hengmei Electronic Technology Co., Ltd.

[0070] The NMR was Model BRUKER AVANCE 400, made by Bruker Corporation, Switzerland.

[0071] Preparation of the phosphine-nitrogen ligand and complex: the relevant solvents were dehydrated by molecular sieve before use.

[0072] Under anhydrous and anaerobic conditions, 100 mmol of 2-aminopyrimidine was dissolved in 200 ml of dichloromethane to obtain reaction solution 1; 220 mmol of triethylamine was added dropwise to the reaction solution 1 under stirring at -5°C; 110 mmol of the compound as shown in structure III (diphenyl chlorophosphine) was slowly added to the solution, and then the remaining 110 mmol of diphenyl chlorophosphine was added after the solution was stable and no longer exothermic; the reaction was stirred for 3 h after the low-temperature constant-temperature reaction bath was removed, and was stirred for 12 h at room temperature. The reaction solution was purified by column chromatography (tetrahydrofuran elution, height-diameter ratio of 2), and then recrystallized at 78°C (solvent: ethanol: ethyl acetate = 5:1); the reaction solution was treated to obtain the product, i.e. the phosphine-nitrogen ligand P1, which has the following structure:

[0073]

[0074] The nuclear magnetic resonance data of the above ligand (P1) are as follows: 1 H NMR (400 MHz, CDCl3): 8.47 (m, 2H), 7.35-7.48 (m, 20H), 6.88 (m, 1H).

[0075] 1 mmol of the phosphine-nitrogen ligand P1 and 1 mmol of tetrahydrofuran chromium chloride were added to 100 ml of toluene and heated to 80°C for stirring for 12 h to generate a blue powder-shaped precipitate; after cooling to room temperature, the toluene was filtered off. The crude product was washed twice with petroleum ether (20 ml) and vacuum dried to obtain the phosphine-nitrogen ligand-chromium complex L1.

[0076] The phosphine-nitrogen ligand P2 is prepared as for P1 except that the compound of structure III added is 4-(trimethylsilyl)phenylphosphine chloride. The structure of P2 is shown below:

[0077]

[0078] The NMR data for the ligand (P2) are as follows: 1 H NMR (400 MHz, CDC13): 8.45 (m, 2H), 7.36-7.40 (m, 16H), 6.93 (m, IH), 0.25 (m, 36H).

[0079] The phosphine-nitrogen ligand-chromium complex L2 is prepared as for L1.

[0080] The phosphine-nitrogen ligand P3: 100 mmol of 5-cyclopropylpyrimidin-2-amine is dissolved in 200 ml of acetonitrile to obtain a reaction solution one; 220 mmol of triethylamine is added dropwise to the reaction solution one under stirring at -5°C; 110 mmol of the compound of structure III (diphenylphosphine chloride) is slowly added to the solution; after the solution is stable and no longer generates heat, the remaining 110 mmol of diphenylphosphine chloride is added; the reaction is stirred for 3 h after which the constant temperature bath is removed and the reaction is stirred at room temperature for 18 h. The reaction solution is purified by column chromatography (tetrahydrofuran elution, height to diameter ratio of 2) and then recrystallized at 80°C (solvent is ethanol: ethyl acetate = 5:1); the reaction solution is treated to obtain the product, which is the ligand P3. The structure of P3 is shown below:

[0081]

[0082] The NMR data for the ligand (P3) are as follows: 1 H NMR (400 MHz, CDC13): 8.58 (m, 2H), 7.38-7.45 (m, 20H), 1.50 (m, IH), 1.24 (m, 2H), 0.99 (m, 2H).

[0083] The phosphine-nitrogen ligand-chromium complex L3 is prepared as for L1.

[0084] Preparation of P4 ligand: The P4 ligand is prepared as in Example 1 except that the compound of structure III added is bis(4-methylphenyl)phosphine chloride. The structure of the ligand P4 is shown below:

[0085]

[0086] The NMR data for the ligand (P4) are as follows: 1H NMR (400 MHz, CDC13): 8.45 (m, 2H), 7.23-7.26 (m, 16H), 6.93 (m, IH), 2.34 (m, 12H).

[0087] Phosphine-nitrogen ligand-chromium complex L4 was prepared according to the preparation of L1.

[0088] Preparation of P5 ligand: 100 mmol of 4,5-dimethoxy-pyrimidin-2-amine was dissolved in 200 ml of acetonitrile to obtain a reaction solution one; 220 mmol of tripropylamine was added dropwise to the reaction solution one under stirring at -5°C; 110 mmol of compound as shown in structure III (diphenylphosphine chloride) was slowly added to the solution, and the remaining 110 mmol of diphenylphosphine chloride was added after the solution was stable and no longer exothermic; the reaction was stirred for 3 h after the low-temperature constant-temperature reaction bath was removed, and was stirred for 18 h at room temperature. The reaction solution was purified by column chromatography (tetrahydrofuran elution, height-diameter ratio of 2), and then recrystallized at 80°C (solvent: ethanol: ethyl acetate = 5:1); the reaction solution was treated to obtain the product, i.e. ligand P5, which has the following structure:

[0089]

[0090] The nuclear magnetic resonance data of the above ligand (P5) are as follows: 1 H NMR (400 MHz, CDC13): 8.45 (m, 2H), 7.23-7.26 (m, 16H), 6.93 (m, IH), 2.34 (m, 12H).

[0091] Phosphine-nitrogen ligand-chromium complex L5 was prepared according to the preparation of L1.

[0092] Preparation of P6 ligand: the preparation method of P6 ligand is the same as that of P1, except that the compound as shown in structure III added is (4-fluorophenyl)(phenyl)phosphine chloride, and the structure of P6 is as follows:

[0093]

[0094] The nuclear magnetic resonance data of the above ligand (P6) are as follows: 1 H NMR (400 MHz, CDC13): 8.45 (m, 2H), 7.23-7.26 (m, 16H), 6.93 (m, IH), 2.34 (m, 12H).

[0095] Phosphine-nitrogen ligand-chromium complex L6 was prepared according to the preparation of L1.

[0096] Preparation of P7 ligand: 100 mmol of 4-isopropoxy pyrimidine-2-amine was dissolved in 200 ml of dichloromethane to obtain a reaction solution one; 220 mmol of triethylamine was added dropwise to the reaction solution one under stirring at -5°C, 110 mmol of compound as shown in structure III (diphenyl phosphine chloride) was slowly added, after the solution was stable and no longer exothermic, the remaining 110 mmol of diphenyl phosphine chloride was added, the reaction was stirred for 3 h, and then the constant temperature bath was removed, and the reaction was stirred at room temperature for 18 h. The reaction solution was purified by column chromatography (tetrahydrofuran elution, height-diameter ratio of 2), and then recrystallized at 80°C (solvent: ethanol: ethyl acetate = 5:1), and the reaction solution was treated to obtain the product, which was ligand P7, and the structure of P7 is shown in the following formula:

[0097]

[0098] The nuclear magnetic resonance data of the above ligand (P7) are as follows: 1 H NMR (400 MHz, CDCl3): 7.38-7.45 (m, 21H), 5.82 (m, 1H), 4.70 (m, 1H), 1.35 (m, 6H).

[0099] Reference L1 to prepare phosphine-nitrogen ligand-chromium complex L7.

[0100] Example 1

[0101] Catalyst combination: phosphine-nitrogen ligand-chromium complex L1, dimethylsilyl (N-tert-butylamine) (tetramethylcyclopentadienyl) titanium dimethyl (T1), and MMAO-3a, Al i Bu3, [Ph3C][B(C6F5)4].

[0102] Polymerization experiment: the two reactors in series are both 500 mL stainless steel reactors, and refined methylcyclohexane is used as the solvent (the solvent is treated by a water and oxygen removal purification system). Before the reaction, the reactor is heated to 120°C, vacuumized for 2 h, and replaced with nitrogen for 3 times. When the temperature cools to room temperature, ethylene is replaced for 3 times:

[0103] S1: the reaction temperature of the first reactor is 50°C, 200 ml of methylcyclohexane, 3.5 μmol of phosphine-nitrogen ligand-chromium complex L1, 1000 μmol of MMAO-3a are added, and the reaction is carried out under the pressure of 4.5 MPa of ethylene to prepare α-olefin. After 30 min, the reaction solution is transferred to the second reactor;

[0104] S2: the temperature of the second reactor is 120°C, 1 μmol of T1, 1 μmol of [Ph3C][B(C6F5)4] and 100 μmol of Al iBu3, the ethylene pressure was adjusted to 0.1 MPa, and the reaction was continued for 40 min. Then, 5 ml of 10% acidified ethanol was added to terminate the reaction. The obtained product was added to 3 wt% activated clay to remove the catalyst residues by adsorption. Subsequently, the filter liquor was obtained by pressure filtration. The solvent and unreacted monomers were removed from the filter liquor by distillation under reduced pressure at 50°C to obtain a poly-alpha-olefin synthetic oil. The test results are shown in Table 1.

[0105] Example 2

[0106] Catalyst combination: phosphine-nitrogen ligand-chromium complex L2, dimethylsilyl(N-tert-butylamido)(tetramethylcyclopentadienyl)dimethyltitanium (T1), and MMAO-3a as the cocatalyst i Bu3, [Ph3C][B(C6F5)4]

[0107] Polymerization experiment: the polymerization experiment was performed as shown in Example 1, except that the phosphine-nitrogen ligand-chromium complex used was L2. The test results of the poly-alpha-olefin synthetic oil are shown in Table 1.

[0108] Example 3

[0109] Catalyst combination: phosphine-nitrogen ligand-chromium complex L2, dimethylsilyl(N-tert-butylamido)(tetramethylcyclopentadienyl)dimethyltitanium (T1), and MMAO-3a as the cocatalyst i Bu3, [Ph3C][B(C6F5)4]

[0110] Polymerization experiment: both the first and second reactors were 500 mL stainless steel reactors, and refined methylcyclohexane was used as the solvent. The reactor was heated to 160°C before the reaction, vacuumized for 1.5 h, and replaced with nitrogen. When the temperature cooled to room temperature, ethylene was replaced:

[0111] (1) The reaction temperature of the first reactor was 60°C, 200 ml of methylcyclohexane, 3.5 μmol of phosphine-nitrogen ligand-chromium complex L2, and 700 μmol of MAO were added, and the reaction was carried out at an ethylene pressure of 5 MPa to prepare alpha-olefins. After 45 min, the reaction solution was transferred to the second reactor.

[0112] (2) The temperature of the second reactor was 140°C, 1 μmol of Z1, 1.2 μmol of tri(p-n-octyl)methyltetra(pentafluorophenyl)borate, and 180 μmol of Al i Bu3, the ethylene pressure was adjusted to 0.1 MPa, and the reaction was continued for 40 min. Then, 5 ml of 10% acidified ethanol was added to terminate the reaction. The obtained product was added to 3 wt% activated clay to remove the catalyst residues by adsorption. Subsequently, the filter liquor was obtained by pressure filtration. The solvent and unreacted monomers were removed from the filter liquor by distillation under reduced pressure at 50°C to obtain a poly-alpha-olefin synthetic oil. The test results are shown in Table 1.

[0113] Example 4

[0114] Catalyst combination: phosphine-nitrogen ligand-chromium complex L2, bis(p-tolylmethylene)cyclopentadienyl(2,7-di-tert-butyl-fluorenyl)zirconium dichloride (Z2), co-catalyst is MMAO-3a, MMAO-7.

[0115] Polymerization experiment: the two reactors in series are both 500 mL stainless steel reactors, and refined methylcyclohexane is used as the solvent. The reactor needs to be heated to 140°C before the reaction, vacuumized for 3h, replaced with nitrogen, and the temperature is cooled to room temperature before ethylene is replaced:

[0116] (1) The reaction temperature of the first reactor is 45°C, 200ml methylcyclohexane, 3.5μmol phosphine-nitrogen ligand-chromium complex L2, 1500μmol MMAO-3a are added, and the reaction is carried out under the condition of setting the ethylene pressure to 5MPa to prepare α-olefin. After 60min of reaction, the reaction solution is transferred to the second reactor;

[0117] (2) The temperature of the second reactor is 150°C, 1μmol of Z2 and 500μmol of MMAO-7 are added, and the ethylene pressure is adjusted to 0.1Mpa. After 60min of continuous reaction, 10ml of 10% acidified ethanol is added to terminate the reaction. The obtained product is added with 3wt% of activated white clay to adsorb and remove the catalyst residues, and then pressure filtration is carried out to obtain the filtrate. The filtrate is subjected to vacuum distillation to remove the solvent and unreacted monomers to obtain poly-α-olefin synthetic oil. The test results are shown in Table 1.

[0118] Example 5

[0119] Catalyst combination: phosphine-nitrogen ligand-chromium complex L2, bis(p-tolylmethylene)cyclopentadienyl(2,7-di-tert-butyl-fluorenyl)zirconium dichloride (Z2), co-catalyst is MMAO-3a, MMAO-7. i Bu3, tris(p-n-octyl)methyltetra(pentafluorophenyl)borate.

[0120] Polymerization experiment: the two reactors in series are both 500 mL stainless steel reactors, and refined methylcyclohexane is used as the solvent. The reactor needs to be heated to 130°C before the reaction, vacuumized for 2h, replaced with nitrogen, and the temperature is cooled to room temperature before ethylene is replaced:

[0121] (1) The reaction temperature of the first reactor is 45°C, 200ml methylcyclohexane, 3.5μmol phosphine-nitrogen ligand-chromium complex L2, 1500μmol MMAO-3a are added, and the reaction is carried out under the condition of setting the ethylene pressure to 5MPa to prepare α-olefin. After 60min of reaction, the reaction solution is transferred to the second reactor;

[0122] (2) The second reactor temperature was 130°C, 1 μmol of T2, 2.5 μmol of [Ph3C][B(C6F5)4] and 100 μmol of MMAO-7 were added, and the ethylene pressure was adjusted to 0.1 MPa. After the reaction was continued for 50 min, 10 ml of 10% acidified ethanol was added to terminate the reaction. The product was added to 3 wt% activated clay to remove the catalyst residues by adsorption, and then pressure filtration was performed to obtain a filtrate. The filtrate was subjected to reduced pressure distillation to remove the solvent and unreacted monomers to obtain a polyalpha-olefin synthetic oil. The test results are shown in Table 1. i Bu3, the ethylene pressure was adjusted to 0.1 MPa, and the reaction was continued for 45 min. Then, 10 ml of 10% acidified ethanol was added to terminate the reaction. The obtained product was added to 2-5 wt% activated clay to remove the catalyst residues by adsorption, and then pressure filtration was performed to obtain a filtrate. The filtrate was subjected to reduced pressure distillation to remove the solvent and unreacted monomers to obtain a polyalpha-olefin synthetic oil. The test results are shown in Table 1.

[0123] Example 6

[0124] Catalyst combination: phosphine-nitrogen ligand-chromium complex L2, dimethylsilyl (N-tert-butylamido) (tetramethylcyclopentadienyl) titanium dichloride (T2), and a cocatalyst of MMAO-7, [Ph3C][B(C6F5)4].

[0125] Polymerization experiment: both reactors were 500 mL stainless steel reactors, and refined methylcyclohexane was used as the solvent. The reactor was heated to 150°C before the reaction, vacuumized for 2 h, and replaced with nitrogen. When the temperature cooled to room temperature, ethylene was replaced:

[0126] (1) The reaction temperature of the first reactor was 50°C, 200 ml of methylcyclohexane, 3.5 μmol of phosphine-nitrogen ligand-chromium complex L2, and 1300 μmol of MMAO-3a were added, and the ethylene pressure was set to 4.5 MPa to prepare alpha-olefins. After 60 min of reaction, the reaction solution was transferred to the second reactor;

[0127] (2) The second reactor temperature was 130°C, 1 μmol of T2, 2.5 μmol of [Ph3C][B(C6F5)4] and 100 μmol of MMAO-7 were added, and the ethylene pressure was adjusted to 0.1 MPa. After the reaction was continued for 50 min, 10 ml of 10% acidified ethanol was added to terminate the reaction. The product was added to 3 wt% activated clay to remove the catalyst residues by adsorption, and then pressure filtration was performed to obtain a filtrate. The filtrate was subjected to reduced pressure distillation to remove the solvent and unreacted monomers to obtain a polyalpha-olefin synthetic oil. The test results are shown in Table 1.

[0128] Example 7

[0129] Catalyst combination: phosphine-nitrogen ligand-chromium complex L3, dimethylsilyl (N-tert-butylamido) (tetramethylcyclopentadienyl) titanium dichloride (T1), and a cocatalyst of MMAO-3a, Al i Bu3, [Ph3C][B(C6F5)4].

[0130] Polymerization experiment: The two reactors in series are both 500 mL stainless steel reactors, and refined methylcyclohexane is used as the solvent (the solvent is treated by a water and oxygen removal purification system). Before the reaction, the reactor is heated to 120°C, vacuumed for 2 h, and replaced with nitrogen for 3 times. When the temperature cools to room temperature, ethylene is replaced for 3 times:

[0131] S1: The reaction temperature of the first reactor is 50°C, 200 ml of methylcyclohexane, 3.5 μmol of phosphine-nitrogen ligand-chromium complex L3, and 2000 μmol of MMAO-3a are added, and the reaction is carried out under the setting of ethylene pressure 4.5 MPa to prepare α-olefin. After 30 min of reaction, the reaction solution is transferred to the second reactor;

[0132] S2: The temperature of the second reactor is 120°C, 1 μmol of T1, 1 μmol of [Ph3C][B(C6F5)4], and 50 μmol of Al i Bu3, adjust the ethylene pressure to 0.1 MPa, continue to react for 40 min, add 5 ml of 10% acidified ethanol to terminate the reaction, add 3 wt% of activated white clay to adsorb and remove the catalyst residues, then pressurize and filter to obtain the filtrate, and then remove the solvent and unreacted monomers from the filtrate by distillation under reduced pressure at 50°C to obtain poly-α-olefin synthetic oil. The test results are shown in Table 1.

[0133] Example 8

[0134] Catalyst combination: phosphine-nitrogen ligand-chromium complex L4, dimethylsilyl (N-tert-butylamine) (tetramethylcyclopentadienyl) titanium dichloride (T2), and co-catalyst MMAO-3a, Al i Bu3, [Ph3C][B(C6F5)4].

[0135] Polymerization experiment: The two reactors in series are both 500 mL stainless steel reactors, and refined methylcyclohexane is used as the solvent (the solvent is treated by a water and oxygen removal purification system). Before the reaction, the reactor is heated to 120°C, vacuumed for 2 h, and replaced with nitrogen for 3 times. When the temperature cools to room temperature, ethylene is replaced for 3 times:

[0136] S1: The reaction temperature of the first reactor is 50°C, 200 ml of methylcyclohexane, 3.5 μmol of phosphine-nitrogen ligand-chromium complex L4, and 350 μmol of MMAO-3a are added, and the reaction is carried out under the setting of ethylene pressure 4.5 MPa to prepare α-olefin. After 30 min of reaction, the reaction solution is transferred to the second reactor;

[0137] S2: The temperature of the second reactor is 120°C, 1 μmol of T2, 1 μmol of [Ph3C][B(C6F5)4], and 200 μmol of Al iBu3, the ethylene pressure was adjusted to 0.1 MPa, and the reaction was continued for 40 min. Then, 5 ml of 10% acidified ethanol was added to terminate the reaction. The obtained product was added to 3 wt% activated clay to adsorb and remove the catalyst residues. Subsequently, the filtrate was obtained by pressure filtration. The filtrate was distilled at 50°C under reduced pressure to remove the solvent and unreacted monomers to obtain a poly-alpha-olefin synthetic oil. The test results are shown in Table 1.

[0138] Example 9

[0139] Catalyst combination: phosphine-nitrogen ligand-chromium complex L5, dimethylsilyl bis(2-methyl-4-phenyl-1-indenyl) zirconium dichloride (Z1), and co-catalyst MMAO-3a, Al i Bu3, [Ph3C][B(C6F5)4].

[0140] Polymerization experiment: both of the two reactors in series were 500 mL stainless steel reactors, and refined methylcyclohexane was used as the solvent (the solvent was treated by a water and oxygen removal purification system). Before the reaction, the reactor was heated to 120°C, vacuumized for 2 h, and replaced with nitrogen for 3 times. When the temperature cooled to room temperature, ethylene was replaced for 3 times:

[0141] S1: the reaction temperature of the first reactor was 50°C, 200 ml of methylcyclohexane, 3.5 μmol of phosphine-nitrogen ligand-chromium complex L5, and 700 μmol of MMAO-3a were added, and the reaction was carried out under the condition of 4.5 MPa of ethylene pressure to prepare alpha-olefins. After 30 min, the reaction solution was transferred to the second reactor;

[0142] S2: the temperature of the second reactor was 120°C, 1 μmol of Z1, 1 μmol of [Ph3C][B(C6F5)4], and 300 μmol of Al i Bu3, the ethylene pressure was adjusted to 0.1 MPa, and the reaction was continued for 40 min. Then, 5 ml of 10% acidified ethanol was added to terminate the reaction. The obtained product was added to 3 wt% activated clay to adsorb and remove the catalyst residues. Subsequently, the filtrate was obtained by pressure filtration. The filtrate was distilled at 50°C under reduced pressure to remove the solvent and unreacted monomers to obtain a poly-alpha-olefin synthetic oil. The test results are shown in Table 1.

[0143] Example 10

[0144] Catalyst combination: phosphine-nitrogen ligand-chromium complex L6, di-p-tolylmethylene cyclopentadiene (2,7-di-tert-butyl-fluorenyl) zirconium dichloride (Z2), and co-catalyst MMAO-3a, Al i Bu3, [Ph3C][B(C6F5)4].

[0145] Polymerization experiment: The two reactors in series are both 500 mL stainless steel reactors, and refined methylcyclohexane is used as the solvent (the solvent is treated by a water and oxygen removal purification system). Before the reaction, the reactor is heated to 120°C, vacuumized for 2 h, and replaced with nitrogen for 3 times. When the temperature cools to room temperature, ethylene is replaced for 3 times:

[0146] S1: The reaction temperature of the first reactor is 50°C, 200 ml of methylcyclohexane, 3.5 μmol of phosphine-nitrogen ligand-chromium complex L6, 2500 μmol of MMAO-3a are added, and the reaction is carried out under the setting of ethylene pressure 4.5 MPa to prepare α-olefin. After 30 min of reaction, the reaction solution is transferred to the second reactor;

[0147] S2: The temperature of the second reactor is 120°C, 1 μmol of Z2, 1 μmol of [Ph3C][B(C6F5)4] and 50 μmol of Al i Bu3, the ethylene pressure is adjusted to 0.1 MPa, and after 40 min of continuous reaction, 5 ml of 10% acidified ethanol is added to terminate the reaction. The obtained product is added with 3 wt% of activated white clay to adsorb and remove the catalyst residues, and then pressure filtration is carried out to obtain the filtrate. The filtrate is distilled at 50°C under reduced pressure to remove the solvent and unreacted monomers to obtain poly-α-olefin synthetic oil. The test results are shown in Table 1.

[0148] Example 11

[0149] Catalyst combination: phosphine-nitrogen ligand-chromium complex L7, diphenyl silyl(cyclopentadienyl)(9-fluorenyl) zirconium dichloride (Z3), and the cocatalyst is MMAO-3a, Al i Bu3, [Ph3C][B(C6F5)4].

[0150] Polymerization experiment: The two reactors in series are both 500 mL stainless steel reactors, and refined methylcyclohexane is used as the solvent (the solvent is treated by a water and oxygen removal purification system). Before the reaction, the reactor is heated to 120°C, vacuumized for 2 h, and replaced with nitrogen for 3 times. When the temperature cools to room temperature, ethylene is replaced for 3 times:

[0151] S1: The reaction temperature of the first reactor is 50°C, 200 ml of methylcyclohexane, 3.5 μmol of phosphine-nitrogen ligand-chromium complex L7, 1000 μmol of MMAO-3a are added, and the reaction is carried out under the setting of ethylene pressure 4.5 MPa to prepare α-olefin. After 30 min of reaction, the reaction solution is transferred to the second reactor;

[0152] S2: The temperature of the second reactor is 120°C, 1 μmol of Z3, 1 μmol of [Ph3C][B(C6F5)4] and 100 μmol of Al iBu3, the ethylene pressure was adjusted to 0.1 MPa, and the reaction was continued for 40 min. Then, 5 ml of 10% acidified ethanol was added to terminate the reaction. The obtained product was added to 3 wt% activated clay to remove the catalyst residues by adsorption. Then, the filtrate was obtained by pressure filtration. The filtrate was distilled at 50°C under reduced pressure to remove the solvent and unreacted monomers to obtain a poly-alpha-olefin synthetic oil. The test results are shown in Table 1.

[0153] Comparative Example 1

[0154] Catalyst combination: dimethylsilyl (N-tert-butylamine) (tetramethylcyclopentadienyl) dimethyl titanium (T1), and the cocatalyst is MMAO-3a, Al i Bu3, [Ph3C][B(C6F5)4].

[0155] Polymerization experiment: the reaction kettle was a 500 mL stainless steel reaction kettle, and refined methylcyclohexane was used as the solvent (the solvent was treated by a water and oxygen removal purification system). Before the reaction, the reaction kettle was heated to 120°C, vacuumized for 2 h, and replaced with nitrogen for 3 times. When the temperature cooled to room temperature, ethylene was replaced for 3 times:

[0156] After the temperature of the reaction kettle was adjusted to 120°C, 1 μmol of T1, 1 μmol of [Ph3C][B(C6F5)4], and 100 μmol of Al i Bu3, the ethylene pressure was adjusted to 0.1 MPa (gauge pressure), and the reaction was continued for 40 min. Then, 5 ml of 10% acidified ethanol was added to terminate the reaction. The obtained product was added to 3 wt% activated clay to remove the catalyst residues by adsorption. Then, the filtrate was obtained by pressure filtration. The filtrate was distilled at 50°C under reduced pressure to remove the solvent and unreacted monomers to obtain a poly-alpha-olefin synthetic oil. The test results are shown in Table 1.

[0157] Table 1 experimental results

[0158]

[0159]

[0160] In summary, the catalyst combination and the method for preparing a poly-alpha-olefin synthetic oil by using the catalyst combination provided by the application can synthesize a series of low-viscosity synthetic oils. By using ethylene as a single raw material and through a double-kettle series process, the viscosity and pour point indexes of the obtained product are similar to those of a direct metallocene catalyst, and the product has excellent market application prospects.

Claims

1. A catalyst composition for preparing polyα-olefin synthetic oil, characterized in that, The catalyst composition comprises a phosphine nitrogen ligand-chromium salt complex, a metallocene catalyst and / or a post-metallocene catalyst, and a co-catalyst. The structure of the phosphine nitrogen ligand-chromium salt complex is shown in Formula I: R1, R2, R3, and R4 are each independently selected from one or more of vinyl, propenyl, cyclohexyl, silyl aryl, alkyl aryl, alkoxy aryl, and fluorinated alkyl; R5, R6, and R7 are each independently selected from one or more of hydrogen, alkyl, and alkoxy.

2. The catalyst composition according to claim 1, characterized in that, In Formula I, R1, R2, R3, and R4 are each independently selected from phenyl, benzyl, biphenyl, naphthyl, anthracene, vinyl, propenyl, 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-di ... One or more of butylphenyl, 2,6-dibutylphenyl, 4-methoxyphenyl, o-methoxyphenyl, 4-ethoxyphenyl, o-ethoxyphenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, and 4-(tri-n-butylsilyl)phenyl; R5, R6, and R7 are each independently selected from one or more of hydrogen, methyl, ethyl, methoxy, ethoxy, isopropoxy, and cyclopropyl.

3. The catalyst composition according to claim 1 or 2, characterized in that, In Formula I, R1, R2, R3, and R4 are each independently selected from 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-ethylphenyl, 2-ethylphenyl, 2-ethylphenyl, 2-ethylphenyl, 4-ethyl ... One or more of the following: 2,4-dibutylphenyl, 2,6-dibutylphenyl, 4-methoxyphenyl, o-methoxyphenyl, 4-ethoxyphenyl, o-ethoxyphenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, and 4-(tri-n-butylsilyl)phenyl.

4. The catalyst composition according to claim 1 or 2, characterized in that, The metallocene catalyst and / or post-metallocene catalyst are selected from one or more of titanium, zirconium, and hafnium catalysts.

5. The catalyst composition according to claim 4, characterized in that, The metallocene catalyst and / or post-metallocene catalyst are selected from dimethicyl(N-tert-butylamino)(tetramethylcyclopentadienyl)titanium dichloride, dimethicyl(N-tert-butylamino)(tetramethylcyclopentadienyl)dimethyltitanium, dimethicyl(N-tert-butylamino)(fluorenyl)titanium dichloride, (pentamethylcyclopentadienyl)trimethoxytitanium, dimethylbis(propylcyclopentadienyl)hafnium, bis(n-butylcyclopentadiene)hafnium dichloride, racemic dimethylsilylbis(2-methyl-1-indenyl)zirconium dichloride, diphenylmethylenecyclopentadiene(2,7-di-tert-butyl-fluorenyl)dichloride Zirconium chloride, di-p-tolymethylenecyclopentadiene(2,7-di-tert-butyl-fluorenyl)zirconium chloride, diphenylmethylene(cyclopentadiene)(9-fluorenyl)zirconium chloride, dimethyldimethylsilylbis(2-methyl-4-phenyl-1-indenyl)zirconium chloride, meso-dimethylsilylbis(1-indenyl)zirconium chloride, bis(methylcyclopentadiene)zirconium chloride, bis(1,3-dimethylcyclopentadienyl)zirconium chloride, cyclopentadienyl(1,2-dimethoxyethane)zirconium trichloride, and diphenylsilyl(cyclopentadiene)(9-fluorenyl)zirconium chloride, are among one or more of these.

6. The catalyst composition according to claim 1, characterized in that, The cocatalyst is selected from organoaluminum compounds and / or organoboron compounds.

7. The catalyst composition according to claim 6, characterized in that, The organoaluminum compound is selected from one or more of alkylaluminum, alkylaluminum chloride, and alkylaluminoxane; The organoboron compound is selected from one or more of borooxanes, alkylborons, borates, and borate esters.

8. The catalyst composition according to claim 7, characterized in that, The organoaluminum compound is selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, diethylethoxyaluminum, dichlorodiethylaluminum, dichloroethylaluminum, sesquiethylaluminum chloride, trioctylaluminum, methylaluminoxane (MAO), modified methylaluminoxane (MMAO), or ethylaluminoxane. The organoboron compound is selected from one or more of the following: cycloboroxane, triethylborane, triphenylborane, triphenylborane amino complex, NaBH4, tributyl borate, triisopropyl borate, tri(pentafluorophenyl)borane, triphenylmethyltetra(pentafluorophenyl)borate, tri(p-octylphenyl)methyltetra(pentafluorophenyl)borate, dimethylphenylammonium tetra(pentafluorophenyl)borate, diethylphenylammonium tetra(pentafluorophenyl)borate, methyldiphenylammonium tetra(pentafluorophenyl)borate, ethyldiphenylammonium tetra(pentafluorophenyl)borate, methyldi(octadecyl)tetra(pentafluorophenyl)borate, and trioctylammonium tetra(pentafluorophenyl)boric acid.

9. The catalyst composition according to claim 1, characterized in that, The molar ratio of the co-catalyst to the phosphine nitrogen ligand-chromium salt complex is 50-2000:1; the molar ratio of the co-catalyst to the metallocene catalyst and / or post-metallocene catalyst is 0.8-1000:

1.

10. The catalyst composition according to claim 9, characterized in that, The molar ratio of the co-catalyst to the phosphine nitrogen ligand-chromium salt complex is 100-1000:1; the molar ratio of the co-catalyst to the metallocene catalyst and / or post-metallocene catalyst is 1-700:

1.

11. Use of a catalyst composition according to any one of claims 1-10, wherein the catalyst composition is used to prepare poly-α-olefin synthetic oil.

12. A method for preparing polyα-olefin synthetic oil, said method using the catalyst composition according to any one of claims 1-10, characterized in that, In the presence of the above-mentioned catalyst composition, the method involves first polymerizing ethylene into high-carbon α-olefins, and then polymerizing them again to prepare polyα-olefin synthetic oil.

13. The method according to claim 12, characterized in that, The method employs a dual-reactor series process.

14. The method according to claim 13, characterized in that, The method includes the following steps: S1: Solvent, phosphine nitrogen ligand-chromium salt complex and co-catalyst are added to the first reaction vessel to prepare α-olefins; S2: The reaction solution is transferred to a second reaction vessel, and a metallocene catalyst and / or a post-metallocene catalyst and a co-catalyst are added to continue the reaction. The reaction is then terminated, the temperature is lowered, and the product is obtained.

15. The method according to claim 14, characterized in that, The reaction temperature of S1 is 35-80℃, and the gauge pressure is 2-6MPa. And / or, after S1 reacts for 15-60 minutes, the reaction solution is transferred to a second reaction vessel; And / or, the solvent in S1 is one or more of benzene compounds, alkanes, and cycloalkanes.

16. The method according to claim 15, characterized in that, The solvent in S1 is one or more of the following: toluene, methylcyclohexane, cyclohexane, n-heptane, n-octane, n-butane, isobutane, n-pentane, cyclopentane, methylcyclopentane, methylenecyclopentane, benzene, xylene, and cumene.

17. The method according to claim 14, characterized in that, The S2 reaction temperature is 100-160℃, and the gauge pressure is 0.05-1MPa; And / or, the reaction is terminated after S2 has reacted for 30-70 minutes.

18. A polyalpha-olefin synthetic oil, wherein the polyalpha-olefin synthetic oil is prepared using the catalyst composition according to any one of claims 1-10, or using the method for preparing polyalpha-olefin synthetic oil according to any one of claims 12-17, characterized in that, The synthetic oil has a viscosity index (VI) > 120 and a pour point < -45℃.

19. A phosphine nitrogen ligand-chromium salt complex, said complex being a complex contained in the catalyst composition according to any one of claims 1-10, characterized in that, The structure of the complex is shown in Formula I: R1, R2, R3, and R4 are each independently selected from one or more of vinyl, propenyl, cyclohexyl, silyl aryl, alkyl aryl, alkoxy aryl, and fluorinated alkyl; R5, R6, and R7 are each independently selected from one or more of hydrogen, alkyl, and alkoxy.

20. The complex according to claim 19, characterized in that, In Formula I, R1, R2, R3, and R4 are each independently selected from phenyl, benzyl, biphenyl, naphthyl, anthracene, vinyl, propenyl, 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-di ... One or more of butylphenyl, 2,6-dibutylphenyl, 4-methoxyphenyl, o-methoxyphenyl, 4-ethoxyphenyl, o-ethoxyphenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, and 4-(tri-n-butylsilyl)phenyl; R5, R6, and R7 are each independently selected from one or more of hydrogen, methyl, ethyl, methoxy, ethoxy, isopropoxy, and cyclopropyl.

21. The complex according to claim 20, characterized in that, In Formula I, R1, R2, R3, and R4 are each independently selected from 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-ethylphenyl, 2-ethylphenyl, 2-ethylphenyl, 2-ethylphenyl, 4-ethyl ... One or more of the following: 2,4-dibutylphenyl, 2,6-dibutylphenyl, 4-methoxyphenyl, o-methoxyphenyl, 4-ethoxyphenyl, o-ethoxyphenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-(trimethylsilyl)phenyl, 3-(trimethylsilyl)phenyl, 4-(trimethylsilyl)phenyl, 2-(tri-n-butylsilyl)phenyl, 3-(tri-n-butylsilyl)phenyl, and 4-(tri-n-butylsilyl)phenyl.

22. The complex according to claim 19, characterized in that, The phosphine nitrogen ligand-chromium salt complex is prepared by phosphine nitrogen ligand and tetrahydrofuran chromium chloride in a solvent. After the formation of a blue powdery precipitate, the mixture is cooled, the solvent is filtered off, washed, and dried to obtain the phosphine nitrogen ligand-chromium salt complex.

23. The complex according to claim 22, characterized in that, The mass ratio of tetrahydrofuran chromium chloride to phosphine-nitrogen ligand is 1:1-1.2, the reaction temperature is 70-120℃, and the stirring time is 7-15h.

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