A method for preparing polyalphaolefin

Abstract

The present invention provides a method for preparing a poly alpha-olefin, comprising: S1. contacting a first metallocene catalyst with a first raw material system comprising a first alpha-olefin and a first solvent, thereby causing a first polymerization reaction of the first alpha-olefin to obtain a first polymerization product; S2. contacting a second metallocene catalyst with a second raw material system comprising a second alpha-olefin and a second solvent, thereby causing a second polymerization reaction of the second alpha-olefin to obtain a second polymerization product; S3. mixing the first polymerization product and the second polymerization product and then performing a third polymerization reaction to obtain the poly alpha-olefin; wherein the first polymerization product and the second polymerization product have different polymerization degrees. The viscosity of the metallocene poly alpha-olefin can be effectively adjusted by the preparation method provided by the present invention.

Description

Technical Field

[0001] The invention relates to the technical field of chemical industry, and in particular to a method for preparing poly-alpha-olefin. Background Art

[0002] Poly-alpha-olefins (PAO) are a type of fully synthetic hydrocarbon lubricant base oil prepared by chemical synthesis. They have the advantages of high viscosity index, excellent low temperature performance, good thermal oxidation stability, low volatility, and good shear stability. They are currently considered to be the most promising fully synthetic lubricant base oil. PAO is usually polymerized by traditional catalysts such as Lewis acid or Zieger-Natta catalysts, such as BF3 for the preparation of low-viscosity PAO, AlCl3 for the preparation of medium-viscosity PAO, and Zieger-Natta for the preparation of high-viscosity PAO.

[0003] Metallocene polyalphaolefin (mPAO) is a product with a comb-like structure and no upright side chains obtained by polymerizing alpha-olefins catalyzed by metallocene catalysts. This structure affects the performance of PAO products. Compared with traditional PAO, mPAO usually has improved rheological properties and flow characteristics, and can provide better shear stability, lower pour point and higher viscosity index, and has good viscosity-temperature characteristics. These characteristics determine that mPAO can be used in highly harsh environments, including powertrain and gear oils, compressor lubricants, transmission fluids and industrial lubricants. As society's requirements for energy utilization and ecological protection become increasingly higher, people's demand for high-performance mPAO lubricant base oils is increasing.

[0004] Metallocene compounds generally refer to a class of organic metal complexes composed of transition metal elements (such as Group IV B elements titanium, zirconium, hafnium) or rare earth metal elements and at least one cyclopentadiene or cyclopentadiene derivative as a ligand. Metallocene catalysts are generally considered to be third-generation PAO catalysts. Adjusting the structure of metallocene compounds, combined with factors such as reactant concentration, reaction temperature, and molecular weight regulators, can adjust the catalytic polymerization degree, thereby affecting the viscosity of the final product PAO. However, the adjustment of the catalyst structure needs to start from basic research, which often increases the progress of PAO product development. Repeated adjustments of processes such as concentration and temperature are carried out in a single reactor, which often affects the stability of the reaction system. The viscosity of metallocene polyalphaolefins is ultimately determined by the content of polymers with different polymerization degrees. To this end, it is necessary to find a way to flexibly adjust the content of polymers with different polymerization degrees to adjust the viscosity of PAO products. Summary of the invention

[0005] In view of the above problems existing in the prior art, one of the objectives of the present invention is to provide a method for preparing poly-α-olefins. The preparation method provided by the present invention can effectively adjust the viscosity of metallocene poly-α-olefins.

[0006] The second object of the present invention is to provide an application of a preparation method corresponding to the first object.

[0007] A third object of the present invention is to provide a poly-α-olefin corresponding to the above object.

[0008] To achieve one of the above purposes, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing poly-alpha-olefin, comprising:

[0010] S1. contacting a first metallocene catalyst with a first raw material system comprising a first α-olefin and a first solvent, thereby causing a first polymerization reaction of the first α-olefin to obtain a first polymerization product;

[0011] S2. contacting a second metallocene catalyst with a second raw material system comprising a second α-olefin and a second solvent, thereby causing a second polymerization reaction of the second α-olefin to obtain a second polymer product;

[0012] S3. After mixing the first polymerization product and the second polymerization product, a third polymerization reaction is performed to obtain the poly-α-olefin;

[0013] Wherein, the first polymerization product and the second polymerization product have different polymerization degrees.

[0014] The inventors of the present application have found through research that, by adopting the above-mentioned preparation method, the process conditions of the first polymerization reaction and the second polymerization reaction can be flexibly adjusted, thereby obtaining the first polymerization product and the second polymerization product with different polymerization degrees. Furthermore, since the first polymerization product and the second polymerization product have different polymerization degrees, the two can affect each other in the mixed system, thereby ultimately comprehensively affecting the viscosity of the product poly-α-olefin.

[0015] According to the present invention, there is no particular limitation on the degree of difference between the first polymerization product and the second polymerization product. By using the method of the present invention, the degree of polymerization of the first polymerization product and the second polymerization product can be flexibly selected according to the viscosity of the final target product poly-α-olefin, as long as the degree of polymerization of the two is different.

[0016] According to the present invention, the mass ratio of the first polymerization product to the second polymerization product is not particularly limited, and the mass ratio can be determined according to the actual demand for viscosity. In some specific embodiments of the present invention, the mass ratio of the first polymerization product to the second polymerization product is 1:(0.01-100), preferably 1:(0.1-10).

[0017] According to some embodiments of the present invention, the first polymerization product and the second polymerization product having different polymerization degrees are obtained by controlling at least one of the following conditions:

[0018] i) controlling the content of the first α-olefin in the first feedstock system to be different from the content of the second α-olefin in the second feedstock system;

[0019] ii) controlling the time of the first polymerization reaction to be different from the time of the second polymerization reaction; and

[0020] iii) controlling the first α-olefin and the second α-olefin to be of different types.

[0021] According to the present invention, the time of the first polymerization reaction can be controlled to be different from the time of the second polymerization reaction to obtain the first polymerization product and the second polymerization product with different polymerization degrees. The content of the first α-olefin in the first raw material system can be controlled to be different from the content of the second α-olefin in the second raw material system to obtain the first polymerization product and the second polymerization product with different polymerization degrees. The time of the first polymerization reaction can be controlled to be different from the time of the second polymerization reaction and the content of the first α-olefin in the first raw material system can be controlled to be different from the content of the second α-olefin in the second raw material system to obtain the first polymerization product and the second polymerization product with different polymerization degrees.

[0022] According to the present invention, the first polymerization product and the second polymerization product having different polymerization degrees obtained in the above manner are beneficial to preparing poly-α-olefin with desired viscosity.

[0023] According to some embodiments of the present invention, in step S3, the mixing method may be to first introduce the first polymerization product into a reaction container for the third polymerization reaction, and then introduce the second polymerization product into a reaction container for the third polymerization reaction; or to first introduce the second polymerization product into a reaction container for the third polymerization reaction, and then introduce the first polymerization product into a reaction container for the third polymerization reaction; or to simultaneously introduce the first polymerization product and the second polymerization product into the reaction container for the third polymerization reaction.

[0024] According to some embodiments of the present invention, in step S3, isopropanol may be used as a terminator to terminate the third polymerization reaction.

[0025] According to some embodiments of the present invention, after the third polymerization reaction is completed, unreacted monomers and oligomerization products can be removed by filtering and distilling under reduced pressure to obtain the final product poly-α-olefin.

[0026] According to some embodiments of the present invention, the filtration and reduced pressure distillation are conventional operations in the art, and the specific operation methods are not described in detail here.

[0027] According to some embodiments of the present invention, the above preparation method can be carried out under an inert atmosphere, for example, under a nitrogen atmosphere.

[0028] In some preferred embodiments of the present invention, in step S1, the temperature of the first raw material system is 30°C to 190°C, preferably 80°C to 170°C.

[0029] In some preferred embodiments of the present invention, in step S2, the temperature of the second raw material system is 30°C to 190°C, preferably 80°C to 170°C.

[0030] In some preferred embodiments of the present invention, the temperature of the first raw material system is the same as the temperature of the second raw material system.

[0031] In some preferred embodiments of the present invention, in step S1, the conditions of the first polymerization reaction include: time of 1 min to 120 min, preferably 5 min to 60 min, and temperature of 30°C to 190°C, preferably 80°C to 170°C.

[0032] According to the present invention, the time of the first polymerization reaction can be listed as 1 min, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 100 min, 110 min, 120 min and any value therebetween.

[0033] In some preferred embodiments of the present invention, in step S2, the conditions of the second polymerization reaction include: time of 1 min to 120 min, preferably 5 min to 60 min, and temperature of 30°C to 190°C, preferably 80°C to 170°C.

[0034] According to the present invention, the time of the second polymerization reaction can be listed as 1 min, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 100 min, 110 min, 120 min and any value therebetween.

[0035] In some preferred embodiments of the present invention, in step S3, the conditions of the third polymerization reaction include: time of 1 min to 360 min, preferably 0.1 h to 5 h, preferably 0.5 h to 3 h, and temperature of 30°C to 190°C, preferably 80°C to 170°C.

[0036] In some preferred embodiments of the present invention, the temperature of the first polymerization reaction, the temperature of the second polymerization reaction and the temperature of the third polymerization reaction are the same.

[0037] According to some embodiments of the present invention, the first raw material system, the second raw material system, the temperature of the first polymerization reaction and the temperature of the second polymerization reaction are the same.

[0038] In some preferred embodiments of the present invention, the first α-olefin and the second α-olefin are the same or different, and are independently selected from one or more of 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene and 1-eicosene.

[0039] In some preferred embodiments of the present invention, the first α-olefin and the second α-olefin are the same or different, and are independently selected from one or more of 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene and 1-tetradecene.

[0040] In some preferred embodiments of the present invention, the first α-olefin and the second α-olefin are the same.

[0041] In some preferred embodiments of the present invention, the first solvent and the second solvent are the same or different, and are independently selected from one or more of alkanes and aromatic hydrocarbons.

[0042] In some preferred embodiments of the present invention, the first solvent and the second solvent are the same or different, and are independently selected from one or more of hexane, heptane, octane, nonane, decane, cyclohexane, benzene, toluene and xylene.

[0043] In some preferred embodiments of the present invention, the first solvent and the second solvent are the same.

[0044] In some preferred embodiments of the present invention, the first metallocene catalyst and the second metallocene catalyst are the same or different, and each independently comprises a metallocene compound and an activator.

[0045] Wherein, the metallocene compound is selected from dimethylsilylbis-n-propylcyclopentadienyl zirconium dichloride, dimethylsilylbis-indenyl zirconium dichloride, diethylsilylbis-indenyl zirconium dichloride, diphenylsilylbis(4,7-dimethylindenyl) zirconium dichloride, dimethylsilylbis(4,7-dimethylindenyl) zirconium dichloride, dimethylsilylbis-indenyl zirconium dichloride, diphenylsilylbis(2-methylcyclopentadienyl) zirconium dichloride, ethylenebis-indenyl zirconium dichloride, ethylenebis-(2-methylindenyl) zirconium dichloride, dimethylsilylbis-(2-methyl-3-butylcyclopentadienyl) zirconium dichloride, dimethylsilylbis-cyclopentadienyl Zirconium dichloride, diethylmethylenecyclopentadienyl (3,5-dimethylphenylindenyl) zirconium dichloride, diethylmethylenecyclopentadienyl (4,7-dimethylindenyl) zirconium dichloride, dimethylmethylenecyclopentadienyl (4,7-dimethylindenyl) zirconium dichloride, dimethylsilylcyclopentadienyl (4,7-dimethylindenyl) zirconium dichloride, dimethylsilylcyclopentadienyl (3,5-dimethylphenylindenyl) zirconium dichloride, dimethylsilylbis (2-methylcyclopentadienyl) zirconium dichloride, dimethylsilylbis (2-methylindenyl) zirconium dichloride Zirconium, dimethylsilylbis-n-propylcyclopentadienyl hafnium dichloride, dimethylsilylbis-indenyl hafnium dichloride, diethylsilylbis-indenyl hafnium dichloride, diphenylsilylbis(4,7-dimethylindenyl) hafnium dichloride, dimethylsilylbis(4,7-dimethylindenyl) hafnium dichloride, dimethylsilylbis-indenyl hafnium dichloride, diphenylsilylbis(2-methylcyclopentadienyl) hafnium dichloride, ethylenebis-indenyl hafnium dichloride, ethylenebis(2-methylindenyl) hafnium dichloride, dimethylsilylbis(2-methyl-3-butylcyclopentadienyl) hafnium dichloride, dimethylsilylbis-cyclopentadienyl hafnium dichloride, diethylmethylene one or more of dimethylsilylcyclopentadienyl (3,5-dimethylphenylindenyl) hafnium dichloride, diethylmethylenecyclopentadienyl (4,7-dimethylindenyl) hafnium dichloride, dimethylmethylenecyclopentadienyl (4,7-dimethylindenyl) hafnium dichloride, dimethylsilylcyclopentadienyl (4,7-dimethylindenyl) hafnium dichloride, dimethylsilylcyclopentadienyl (3,5-dimethylphenylindenyl) hafnium dichloride, dimethylsilylbis (2-methylcyclopentadienyl) hafnium dichloride, dimethylsilylbis (2-methylindenyl) hafnium dichloride and dimethylsilylcyclopentadienyl (2-methylindenyl) hafnium dichloride;

[0046] The activator is selected from one or more of alkyl aluminum and borate.

[0047] According to some embodiments of the present invention, the activator comprises at least one aluminum alkyl and at least one borate. In this case, the weight ratio of the aluminum alkyl to the borate may be 1:(0.01-200), preferably 1:(0.01-10).

[0048] According to some embodiments of the present invention, the metallocene catalyst may be a mixture or an interaction product of the metallocene compound and an activator.

[0049] In some preferred embodiments of the present invention, the general formula of the alkyl aluminum is AlR3, wherein R is C1-C 10 alkyl.

[0050] In some preferred embodiments of the present invention, the alkylaluminum is selected from one or more of trimethylaluminum, triethylaluminum, triisopropylaluminum, tri-n-propylaluminum, triisobutylaluminum, tri-n-butylaluminum, triisopentylaluminum, tri-n-pentylaluminum, triisohexylaluminum, tri-n-hexylaluminum, triisoheptylaluminum, tri-n-heptylaluminum, triisooctylaluminum, tri-n-octylaluminum, triisononylaluminum, tri-n-nonylaluminum, triisodecylaluminum and tri-n-decylaluminum.

[0051] In some preferred embodiments of the present invention, the borate is selected from one or more of tetrakis(pentafluorophenyl)borate dimethylanilinium salt, tetrakis(pentafluorophenyl)borate diethylanilinium salt, tetrakis(pentafluorophenyl)borate dibutylanilinium salt, tetrakis(pentafluorophenyl)borate trimethylammonium salt, tetrakis(pentafluorophenyl)borate diethylammonium salt and tetrakis(pentafluorophenyl)borate tributylammonium salt.

[0052] In some preferred embodiments of the present invention, the first metallocene catalyst and the second metallocene catalyst are the same.

[0053] In some preferred embodiments of the present invention, in step S1, the amount of the first solvent used is 1 mL to 1000 mL, preferably 1 mL to 500 mL, per gram of the first α-olefin.

[0054] In some preferred embodiments of the present invention, in step S2, the amount of the second solvent used is 1 mL to 1000 mL, preferably 1 mL to 500 mL, per gram of the second α-olefin.

[0055] According to some embodiments of the present invention, the amount of the first solvent used may be the same as or different from the amount of the second solvent used.

[0056] In some preferred embodiments of the present invention, in step S1, the weight ratio of the metallocene compound, the activator and the first α-olefin is 1:(10-1000):(100-100000).

[0057] In some preferred embodiments of the present invention, in step S2, the weight ratio of the metallocene compound, the activator and the second α-olefin is 1:(10-1000):(100-100000).

[0058] In some specific embodiments of the present invention, per 100 mL of the first metallocene catalyst or the second metallocene catalyst, the content of the metallocene compound may be 1 μmol to 20 μmol, the content of the alkyl aluminum may be 10 mg to 1000 mg, and the content of the borate may be 5 mg to 500 mg.

[0059] According to some embodiments of the present invention, the amount of the first metallocene catalyst used and the amount of the second metallocene catalyst used may be the same or different.

[0060] According to some embodiments of the present invention, the device for implementing the preparation method includes three reaction devices. Specifically, the third reaction device is respectively connected to the first reaction device and the second reaction device, and there is no connection relationship between the first reaction device and the second reaction device.

[0061] To achieve the second purpose above, the technical solution adopted by the present invention is as follows:

[0062] An application of the above preparation method in the field of preparation of poly-alpha-olefins.

[0063] An application of the preparation method in the field of preparation of poly-alpha-olefins with different viscosity grades.

[0064] According to some embodiments of the present invention, the poly α-olefin may be a homopolymer or copolymer formed by one or more of 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene and 1-eicosene.

[0065] To achieve the third purpose above, the technical solution adopted by the present invention is as follows:

[0066] A poly-α-olefin prepared according to the above preparation method, wherein the viscosity index of the poly-α-olefin is above 140; and / or the weight average molecular weight of the poly-α-olefin is 200-200000; and / or the kinematic viscosity of the poly-α-olefin at 100°C is above 3 cSt.

[0067] According to some preferred embodiments of the present invention, the kinematic viscosity of the poly-α-olefin at 100° C. is between 3 cSt and 5000 cSt.

[0068] According to some embodiments of the present invention, the viscosity of the polymerization product can be adjusted by adjusting the amount of the polymerization monomer (i.e., the first α-olefin and / or the second α-olefin), by adjusting the time of the first polymerization reaction and the second polymerization reaction, or by adjusting the type of α-olefin.

[0069] In the present invention, the term "same" may also be understood as substantially the same, for example, the difference is within 1% or even 5%. This is because the difference within 5% or even 1% has little effect on the result and can be ignored and regarded as the same.

[0070] The beneficial effects of the present invention are at least in the following aspects:

[0071] Firstly, the preparation method provided by the present invention is simple and easy to operate, and the viscosity of the poly-α-olefin can be effectively adjusted only by changing the process conditions.

[0072] Secondly, the preparation method provided by the present invention can prepare poly-α-olefin products with different viscosity levels to meet the needs of different occasions or products. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 It is a process flow chart of Example 1 of the present invention. DETAILED DESCRIPTION

[0074] The present invention is described in detail below by way of examples, but the protection scope of the present invention is not limited to the following description.

[0075] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be obtained through commercial channels.

[0076] Yield = m1 / m2×100%, where m1 is the mass of the polymerized product and m2 is the total mass of the polymerized monomers.

[0077] Example 1

[0078] Reaction I: 50 g of 1-octene and 200 mL of toluene were added to a 500 mL flask filled with nitrogen, and heated at 100° C. for 30 minutes. Then, 50 mL of a metallocene catalyst solution (3 μmol of diethylsilylbisindenylzirconium dichloride, 50 mg of dimethylanilinium tetrakis(pentafluorophenyl)borate, and 35 mg of triethylaluminum) was added.

[0079] Reaction II: 100 g of 1-octene and 200 mL of toluene were added to a 500 mL flask filled with nitrogen, heated at 100° C. for 30 minutes, and 50 mL of a metallocene catalyst solution (3 μmol of diethylsilylbisindenylzirconium dichloride, 50 mg of dimethylanilinium tetrakis(pentafluorophenyl)borate, and 35 mg of triethylaluminum) was added.

[0080] Reaction III: A 1000 mL flask filled with nitrogen was heated at 100°C.

[0081] In the above reaction, reaction I and reaction II were reacted simultaneously for 10 min and then transferred to reaction III at the same time. After reacting for 1 hour, a small amount of isopropanol was added to terminate the reaction.

[0082] After cooling to room temperature, the mixture was filtered and distilled under reduced pressure to obtain 136.5 g of product with a yield of 91%. The obtained product was tested, and the results showed that the kinematic viscosity at 100°C was 50 cSt, the viscosity index was 183, and the weight average molecular weight was 3451.

[0083] Example 2

[0084] Example 2 is substantially the same as Example 1, except that the amount of 1-octene in reaction II is adjusted to 200 g.

[0085] After cooling to room temperature, the mixture was filtered and distilled under reduced pressure to obtain 222.5 g of product with a yield of 89%. The obtained product was tested, and the results showed that the kinematic viscosity at 100°C was 85 cSt, the viscosity index was 196, and the weight average molecular weight was 4925.

[0086] Example 3

[0087] Reaction I and reaction II of Example 3 are the same as those of Example 1, and reaction III is:

[0088] A 1000 mL flask filled with nitrogen was heated at a constant temperature of 100° C. After reaction I was reacted for 5 min and reaction II was reacted for 10 min, the mixture was transferred to reaction III at the same time. After reaction for 1 hour, a small amount of isopropanol was added to terminate the reaction.

[0089] After cooling to room temperature, the mixture was filtered and distilled under reduced pressure to obtain 140 g of product with a yield of 93%. The obtained product was tested and the results showed that the kinematic viscosity at 100°C was 15 cSt, the viscosity index was 156, and the weight average molecular weight was 2306.

[0090] Example 4

[0091] Reaction I and reaction II of Example 4 are the same as those of Example 1, and reaction III is:

[0092] A 1000 mL flask filled with nitrogen was heated at a constant temperature of 100° C. After reaction I was reacted for 10 min and reaction II was reacted for 20 min, the mixture was transferred to reaction III at the same time. After reaction for 1 hour, a small amount of isopropanol was added to terminate the reaction.

[0093] After cooling to room temperature, the mixture was filtered and distilled under reduced pressure to obtain 132 g of product with a yield of 88%. The obtained product was tested, and the results showed that the kinematic viscosity at 100°C was 93 cSt, the viscosity index was 201, and the weight average molecular weight was 4837.

[0094] Example 5

[0095] Reaction I: 50 g of 1-octene and 200 mL of toluene were added to a 500 mL flask filled with nitrogen, and heated at 85° C. for 30 minutes. Then, 50 mL of a metallocene catalyst solution (3 μmol of diethylsilylbisindenylzirconium dichloride, 50 mg of dimethylanilinium tetrakis(pentafluorophenyl)borate, and 35 mg of triethylaluminum) was added.

[0096] Reaction II: 100 g of 1-octene and 200 mL of toluene were added to a 500 mL flask filled with nitrogen, heated at 85° C. for 30 minutes, and 50 mL of a metallocene catalyst solution (3 μmol of diethylsilylbisindenylzirconium dichloride, 50 mg of dimethylanilinium tetrakis(pentafluorophenyl)borate, and 35 mg of triethylaluminum) was added.

[0097] Reaction III: A 1000 mL flask filled with nitrogen was heated at 85°C. After reaction I and reaction II were reacted for 10 min, they were transferred to reaction III at the same time. After reacting for 1 hour, a small amount of isopropanol was added to terminate the reaction.

[0098] After cooling to room temperature, the mixture was filtered and distilled under reduced pressure to obtain 142 g of product with a yield of 95%. The obtained product was tested, and the results showed that the kinematic viscosity at 100°C was 103 cSt, the viscosity index was 200, and the weight average molecular weight was 5722.

[0099] Example 6

[0100] Reaction I: 50 g of 1-octene and 200 mL of toluene were added to a 500 mL flask filled with nitrogen, and heated at 135° C. for 30 minutes. Then, 50 mL of a metallocene catalyst solution (3 μmol of diethylsilylbisindenylzirconium dichloride, 50 mg of dimethylanilinium tetrakis(pentafluorophenyl)borate, and 35 mg of triethylaluminum) was added.

[0101] Reaction II: 100 g of 1-octene and 200 mL of toluene were added to a 500 mL flask filled with nitrogen, heated at 135° C. for 30 minutes, and 50 mL of a metallocene catalyst solution (3 μmol of diethylsilylbisindenylzirconium dichloride, 50 mg of dimethylanilinium tetrakis(pentafluorophenyl)borate, and 35 mg of triethylaluminum) was added.

[0102] Reaction III: A 1000 mL flask filled with nitrogen was heated at a constant temperature of 135°C. After reaction I and reaction II were reacted for 10 min simultaneously, they were transferred to reaction III at the same time. After reacting for 1 hour, a small amount of isopropanol was added to terminate the reaction.

[0103] After cooling to room temperature, the mixture was filtered and distilled under reduced pressure to obtain 130 g of product with a yield of 87%. The obtained product was tested, and the results showed that the kinematic viscosity at 100°C was 10 cSt, the viscosity index was 155, and the weight average molecular weight was 2346.

[0104] Example 7

[0105] Reaction I: 50 g of 1-octene and 200 mL of toluene were added to a 500 mL flask filled with nitrogen, and heated at 80° C. for 30 minutes. Then, 50 mL of a metallocene catalyst solution (3 μmol of diethylsilylbisindenylzirconium dichloride, 50 mg of dimethylanilinium tetrakis(pentafluorophenyl)borate, and 35 mg of triethylaluminum) was added.

[0106] Reaction II: 100 g of 1-octene and 200 mL of toluene were added to a 500 mL flask filled with nitrogen, heated at 100° C. for 30 minutes, and 50 mL of a metallocene catalyst solution (3 μmol of diethylsilylbisindenylzirconium dichloride, 50 mg of dimethylanilinium tetrakis(pentafluorophenyl)borate, and 35 mg of triethylaluminum) was added.

[0107] Reaction III: A 1000 mL flask filled with nitrogen was heated at a constant temperature of 100°C. After reaction I and reaction II were reacted for 10 min, they were transferred to reaction III at the same time. After reacting for 1 hour, a small amount of isopropanol was added to terminate the reaction.

[0108] After cooling to room temperature, the mixture was filtered and distilled under reduced pressure to obtain 136 g of product with a yield of 91%. The obtained product was tested, and the results showed that the kinematic viscosity at 100°C was 65 cSt, the viscosity index was 185, and the weight average molecular weight was 4416.

[0109] Example 8

[0110] Reaction I: 50 g of 1-octene and 200 mL of toluene were added to a 500 mL flask filled with nitrogen, and heated at 100° C. for 30 minutes. Then, 50 mL of a metallocene catalyst solution (3 μmol of diethylsilylbisindenylzirconium dichloride, 50 mg of dimethylanilinium tetrakis(pentafluorophenyl)borate, and 35 mg of triethylaluminum) was added.

[0111] Reaction II: 100 g of 1-octene and 200 mL of toluene were added to a 500 mL flask filled with nitrogen, heated at 100° C. for 30 minutes, and 50 mL of a metallocene catalyst solution (3 μmol of dimethylsilylbis(2-methylcyclopentadienyl)zirconium dichloride, 50 mg of dimethylanilinium tetrakis(pentafluorophenyl)borate, and 35 mg of triethylaluminum) was added.

[0112] Reaction III: A 1000 mL flask filled with nitrogen was heated at a constant temperature of 100°C. After reaction I and reaction II were reacted for 10 min, they were transferred to reaction III at the same time. After reacting for 1 hour, a small amount of isopropanol was added to terminate the reaction.

[0113] After cooling to room temperature, the mixture was filtered and distilled under reduced pressure to obtain 138 g of product with a yield of 92%. The obtained product was tested, and the results showed that the kinematic viscosity at 100°C was 25 cSt, the viscosity index was 175, and the weight average molecular weight was 3042.

[0114] Example 9

[0115] Reaction I: 50 g of 1-octene and 200 mL of toluene were added to a 500 mL flask filled with nitrogen, and heated at 100° C. for 30 minutes. Then, 50 mL of a metallocene catalyst solution (3 μmol of diethylsilylbisindenylzirconium dichloride, 50 mg of dimethylanilinium tetrakis(pentafluorophenyl)borate, and 35 mg of triethylaluminum) was added.

[0116] Reaction II: 100 g of 1-dodecene and 200 mL of toluene were added to a 500 mL flask filled with nitrogen, heated at 100° C. for 30 minutes, and 50 mL of a metallocene catalyst solution (3 μmol of diethylsilylbisindenylzirconium dichloride, 50 mg of dimethylanilinium tetrakis(pentafluorophenyl)borate, and 35 mg of triethylaluminum) was added.

[0117] Reaction III: A 1000 mL flask filled with nitrogen was heated at a constant temperature of 100°C. After reaction I and reaction II were reacted for 10 min, they were transferred to reaction III at the same time. After reacting for 1 hour, a small amount of isopropanol was added to terminate the reaction.

[0118] After cooling to room temperature, the mixture was filtered and distilled under reduced pressure to obtain 132 g of product with a yield of 88%. The obtained product was tested, and the results showed that the kinematic viscosity at 100°C was 70 cSt, the viscosity index was 190, and the weight average molecular weight was 4388.

[0119] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A method for preparing a poly-alpha-olefin, comprising: S1. contacting a first metallocene catalyst with a first raw material system comprising a first α-olefin and a first solvent, thereby causing a first polymerization reaction of the first α-olefin to obtain a first polymerization product; S2. contacting a second metallocene catalyst with a second raw material system comprising a second α-olefin and a second solvent, thereby causing a second polymerization reaction of the second α-olefin to obtain a second polymer product; S3. After mixing the first polymerization product and the second polymerization product, a third polymerization reaction is performed to obtain the poly-α-olefin; wherein the first polymerization product and the second polymerization product have different degrees of polymerization; The first polymerization product and the second polymerization product having different polymerization degrees are obtained by controlling at least one of the following conditions: i) controlling the content of the first α-olefin in the first feedstock system to be different from the content of the second α-olefin in the second feedstock system; ii) controlling the time of the first polymerization reaction to be different from the time of the second polymerization reaction; and iii) controlling the first α-olefin and the second α-olefin to be different in type; In step S1, the temperature of the first raw material system is 30°C to 190°C; the conditions of the first polymerization reaction include: time is 1 min to 120 min, and temperature is 30°C to 190°C; In step S2, in step S2, the temperature of the second raw material system is 30°C to 190°C; the conditions of the second polymerization reaction include: time is 1min to 120min, temperature is 30°C to 190°C; In step S3, the conditions of the third polymerization reaction include: time of 1 min to 360 min, temperature of 30° C. to 190° C.; The first α-olefin and the second α-olefin are different and are each independently selected from one or more of 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene and 1-eicosene; The kinematic viscosity of the poly-α-olefin at 100° C. is 3 cSt to 5000 cSt.

2. The preparation method according to claim 1, characterized in that: In step S1, the temperature of the first raw material system is 80°C to 170°C; the conditions of the first polymerization reaction include: time is 5min to 60min, temperature is 80°C to 170°C; And / or, in step S2, the temperature of the second raw material system is 80°C to 170°C; the conditions of the second polymerization reaction include: time is 5min to 60min, temperature is 80°C to 170°C; And / or, in step S3, the conditions of the third polymerization reaction include: time of 0.1h~5h, temperature of 80°C~170°C.

3. The preparation method according to claim 2, characterized in that: In step S3, the conditions of the third polymerization reaction include: time is 0.5h~3h.

4. The preparation method according to claim 2, characterized in that: The temperature of the first raw material system is the same as the temperature of the second raw material system; the temperature of the first polymerization reaction, the temperature of the second polymerization reaction and the temperature of the third polymerization reaction are the same.

5. The preparation method according to claim 1, characterized in that: The first α-olefin and the second α-olefin are different and are each independently selected from one or more of 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene and 1-tetradecene.

6. The preparation method according to claim 1, characterized in that: The first solvent and the second solvent are the same or different, and are independently selected from one or more of alkanes and aromatic hydrocarbons.

7. The preparation method according to claim 6, characterized in that: The first solvent and the second solvent are the same or different, and are independently selected from one or more of hexane, heptane, octane, nonane, decane, cyclohexane, benzene, toluene and xylene.

8. The preparation method according to claim 7, characterized in that: The first solvent and the second solvent are the same.

9. The preparation method according to claim 1, characterized in that: The first metallocene catalyst and the second metallocene catalyst are the same or different, and each independently comprises a metallocene compound and an activator, Wherein, the metallocene compound is selected from dimethylsilylbis-n-propylcyclopentadienyl zirconium dichloride, dimethylsilylbis-indenyl zirconium dichloride, diethylsilylbis-indenyl zirconium dichloride, diphenylsilylbis(4,7-dimethylindenyl) zirconium dichloride, dimethylsilylbis(4,7-dimethylindenyl) zirconium dichloride, dimethylsilylbis-indenyl zirconium dichloride, diphenylsilylbis(2-methylcyclopentadienyl) zirconium dichloride, ethylenebis-indenyl zirconium dichloride, ethylenebis-(2-methylindenyl) zirconium dichloride, dimethylsilylbis-(2-methyl-3-butylcyclopentadienyl) zirconium dichloride, dimethylsilylbis-cyclopentadienyl Zirconium dichloride, diethylmethylenecyclopentadienyl (3,5-dimethylphenylindenyl) zirconium dichloride, diethylmethylenecyclopentadienyl (4,7-dimethylindenyl) zirconium dichloride, dimethylmethylenecyclopentadienyl (4,7-dimethylindenyl) zirconium dichloride, dimethylsilylcyclopentadienyl (4,7-dimethylindenyl) zirconium dichloride, dimethylsilylcyclopentadienyl (3,5-dimethylphenylindenyl) zirconium dichloride, dimethylsilylbis (2-methylcyclopentadienyl) zirconium dichloride, dimethylsilylbis (2-methylindenyl) zirconium dichloride Zirconium, dimethylsilylbis-n-propylcyclopentadienyl hafnium dichloride, dimethylsilylbis-indenyl hafnium dichloride, diethylsilylbis-indenyl hafnium dichloride, diphenylsilylbis(4,7-dimethylindenyl) hafnium dichloride, dimethylsilylbis(4,7-dimethylindenyl) hafnium dichloride, dimethylsilylbis-indenyl hafnium dichloride, diphenylsilylbis(2-methylcyclopentadienyl) hafnium dichloride, ethylenebis-indenyl hafnium dichloride, ethylenebis(2-methylindenyl) hafnium dichloride, dimethylsilylbis(2-methyl-3-butylcyclopentadienyl) hafnium dichloride, dimethylsilylbis-cyclopentadienyl hafnium dichloride, diethylmethylene one or more of dimethylcyclopentadienyl (3,5-dimethylphenylindenyl) hafnium dichloride, diethylmethylenecyclopentadienyl (4,7-dimethylindenyl) hafnium dichloride, dimethylmethylenecyclopentadienyl (4,7-dimethylindenyl) hafnium dichloride, dimethylsilylcyclopentadienyl (4,7-dimethylindenyl) hafnium dichloride, dimethylsilylcyclopentadienyl (3,5-dimethylphenylindenyl) hafnium dichloride, dimethylsilylbis (2-methylcyclopentadienyl) hafnium dichloride, dimethylsilylbis (2-methylindenyl) hafnium dichloride and dimethylsilylcyclopentadienyl (2-methylindenyl) hafnium dichloride; The activator is selected from one or more of alkyl aluminum and borate.

10. The preparation method according to claim 9, characterized in that: The general formula of alkyl aluminum is AlR3, where R is a C1-C10 alkyl group.

11. The preparation method according to claim 10, characterized in that: The alkylaluminum is selected from one or more of trimethylaluminum, triethylaluminum, triisopropylaluminum, tri-n-propylaluminum, triisobutylaluminum, tri-n-butylaluminum, triisopentylaluminum, tri-n-pentylaluminum, triisohexylaluminum, tri-n-hexylaluminum, triisoheptylaluminum, tri-n-heptylaluminum, triisooctylaluminum, tri-n-octylaluminum, triisononylaluminum, tri-n-nonylaluminum, triisodecylaluminum and tri-n-decylaluminum; the borate is selected from one or more of tetrakis(pentafluorophenyl)borate dimethylanilinium salt, tetrakis(pentafluorophenyl)borate diethylanilinium salt, tetrakis(pentafluorophenyl)borate dibutylanilinium salt, tetrakis(pentafluorophenyl)borate trimethylammonium salt, tetrakis(pentafluorophenyl)borate diethylammonium salt and tetrakis(pentafluorophenyl)borate tributylammonium salt.

12. The preparation method according to claim 1, characterized in that: In step S1, the amount of the first solvent used is 1 mL to 1000 mL per gram of the first α-olefin; and / or in step S2, the amount of the second solvent used is 1 mL to 1000 mL per gram of the second α-olefin.

13. The preparation method according to claim 12, characterized in that: In step S1, the amount of the first solvent used is 1 mL to 500 mL per gram of the first α-olefin; and / or in step S2, the amount of the second solvent used is 1 mL to 500 mL per gram of the second α-olefin.

14. The preparation method according to any one of claims 9 to 13, characterized in that: In step S1, the weight ratio of the metallocene compound, the activator and the first α-olefin is 1:(10~1000):(100~100000); and / or in step S2, the weight ratio of the metallocene compound, the activator and the second α-olefin is 1:(10~1000):(100~100000).

15. Use of the preparation method according to any one of claims 1 to 14 in the field of preparation of poly-α-olefins.

16. The use according to claim 15, characterized in that The application is application in the field of preparation of poly-α-olefins with different viscosity grades.

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