A method for preparing an ultra-high molecular weight polyalphaolefin

Abstract

The application discloses a preparation method of ultrahigh molecular weight poly-alpha-olefin, which uses one or more alpha-olefins as polymerization monomers, and carries out polymerization reaction under the action of a catalyst at-30-30 DEG C; the catalyst comprises a main catalyst, a cocatalyst and an external electron donor; the main catalyst is a solid catalyst component, which comprises magnesium, titanium, chlorine and an internal electron donor, and the mass ratio of the four is 1:10-100:20-400:1-5; the internal electron donor contains at least one dihydric alcohol ester compound; the cocatalyst is an alkyl aluminum compound; the external electron donor is selected from organosiloxane; and the molar ratio of the main catalyst (calculated according to titanium): the cocatalyst (calculated according to aluminum): the external electron donor (calculated according to silicon) is 1:10-500:0-500. The poly-alpha-olefin prepared by the method has a weight average molecular weight close to 10 million, and the drag reduction agent prepared from the poly-alpha-olefin has excellent drag reduction performance.

Description

Technical Field

[0001] This invention belongs to the field of olefin polymerization technology, specifically relating to a method for preparing ultra-high molecular weight polyα-olefins. Background Technology

[0002] Since the successful application of drag-reducing agents for oil products manufactured by Conoco in the United States to Alaska crude oil pipelines in 1979, the development of drag-reducing agents has been extremely rapid. In the nearly 50 years of research on drag-reducing agents for oil products by researchers both domestically and internationally, it has been discovered that high molecular weight oil-soluble polyalphaolefins (PAOs) are the best drag-reducing polymers. It is a non-polar polymer that dissolves rapidly in oil, exhibiting a comb-like structure in the oil flow, which can effectively reduce the flow resistance of oil in turbulent conditions. Generally, the higher the molecular weight of the PAO, the higher the drag reduction rate of the drag-reducing agent, and the better it can alleviate the flow resistance of oil products. However, its production conditions are difficult to control, requiring strictly anhydrous and oxygen-free conditions.

[0003] Ultra-high molecular weight (UHMW) polyolefins refer to linear polyolefins with an average molecular weight of 3 million or more (ISO standard) or an average molecular weight of 1.5 million or more (ASTM standard). The polymerization methods for producing UHMW polyalphaolefins include bulk polymerization and slurry polymerization. Bulk polymerization is generally used, but the polymer obtained by bulk polymerization is in large blocks, requiring subsequent grinding into fine particles at low temperatures. This process involves many steps and consumes a lot of energy.

[0004] CN105330872A discloses a method for preparing a drag-reducing agent slurry. This invention utilizes slurry polymerization with silicone oil as a solvent to synthesize polyα-olefins. The catalytic system can be Ziegler-Natta type, metallocene type, or non-metallocene type. However, the drag-reducing agent formulated from the obtained polymer achieves a drag reduction rate of only 40%, which is relatively low.

[0005] In 2018, the doctoral dissertation "Research on Preparation and Application Technology of Oil-soluble Drag Reducers by Slurry Polymerization" from China University of Petroleum prepared oil-soluble drag reducers suitable for crude oil and refined oil using slurry polymerization and conducted application research. However, the weight-average molecular weight of its key component, polyα-olefin, reached a maximum of 4 million, which is relatively low.

[0006] The higher the molecular weight of polyalphaolefins, the better the drag-reducing performance of the drag-reducing agent. However, excessively high molecular weight reduces the solubility of the drag-reducing agent in oils, thereby reducing its drag-reducing performance. Generally, the molecular weight of polyalphaolefins is controlled between 6 million and 10 million. Obtaining high molecular weight polymers requires extremely stringent system conditions, such as controlling the moisture content below 25 ppm.

[0007] Therefore, developing a method for preparing ultra-high molecular weight polyα-olefins is of great significance for the application of drag reducers in oil products. Summary of the Invention

[0008] Objective of the Invention: The objective of this invention is to address the shortcomings of existing technologies by providing a method for preparing ultra-high molecular weight polyalphaolefins (UHMWPEs). This invention utilizes a highly active Ziegler-Natta catalyst with a particle size less than 50 μm containing a special internal electron donor, reacting it in a reaction-inert silicone oil solvent to obtain small UHMWPE particles suspended in the silicone oil solvent. After filtration, a white, loosely dispersed UHMWPE is obtained, which can be used as a main agent in the formulation of oil drag-reducing agents with excellent drag-reducing properties.

[0009] Technical solution: The objective of this invention is achieved through the following technical solution:

[0010] This invention provides a method for preparing ultra-high molecular weight polyα-olefins, which uses one or more α-olefins as polymerization monomers and carries out a polymerization reaction at -30 to 30°C under the action of a catalyst.

[0011] The catalyst includes a main catalyst, a co-catalyst, and an external electron donor;

[0012] The main catalyst is a solid catalyst component, which includes magnesium, titanium, chlorine and an internal electron donor, with a mass ratio of 1:10-100:20-400:1-5.

[0013] The internal electron donor contains at least one diol ester compound selected from general formula I below:

[0014]

[0015] in,

[0016] R1 and R2 may be the same or different, and are selected from substituted or unsubstituted C1-C. 20 Straight-chain alkyl, branched alkyl, cycloalkyl, aryl, alkylaryl, aralkyl, olefinic or fused-ring aryl;

[0017] A is selected from a divalent spar group of alkyl, cycloalkyl, or aryl groups having 1 to 20 carbon atoms; the divalent spar group is optionally separated by C1-C2. 20 The straight-chain or branched alkyl group is substituted, wherein the carbon atom and / or hydrogen atom in the divalent styrene group and its substituents are optionally substituted with nitrogen, oxygen, sulfur, silicon, phosphorus or halogen, and the substituents on the divalent styrene group are optionally or arbitrarily bonded to one or more saturated / unsaturated rings.

[0018] Examples include: 2,4-pentanediol dibenzoate, 3,5-heptanediol dibenzoate, 4-ethyl-3,5-heptanediol dibenzoate, 3,5-heptanediol di-p-methylbenzoate, 3,5-heptanediol di-o-methylbenzoate, 3,5-heptanediol di-p-chlorobenzoate, 3,5-heptanediol di-o-chlorobenzoate, 3,5-heptanediol di-p-methoxybenzoate, 3,5-heptanediol di-o-methoxybenzoate, 3,5-heptanediol di-m-methoxybenzoate, 2-methyl-3,5-heptanediol dibenzoate, 4-methyl-3,5-heptanediol dibenzoate, 6-methyl-3,5-heptanediol dibenzoate, 4-ethyl-3,5-heptanediol dibenzoate, 5-ethyl-3,5-heptanediol dibenzoate. 4-propyl-3,5-heptanediol dibenzoate, 4-butyl-3,5-heptanediol dibenzoate, 2,4-dimethyl-3,5-heptanediol dibenzoate, 2,6-dimethyl-3,5-heptanediol dibenzoate, 4,4-dimethyl-3,5-heptanediol dibenzoate, 6,6-dimethyl-3,5-heptanediol dibenzoate, 4,4-dimethyl-3,5-heptanediol dibenzoate, 6,6-dimethyl-3,5-heptanediol dibenzoate, 2-methyl-4-ethyl-3,5-heptanediol dibenzoate, 4-methyl-4-ethyl-3,5-heptanediol dibenzoate, 2-methyl-4-propyl-3,5-heptanediol dibenzoate Benzoate esters, 4-methyl-4-propyl-3,5-heptanediol dibenzoate, 6-methyl-2,4-heptanediol di(p-chlorobenzoic acid), 6-methyl-2,4-heptanediol di(p-methylbenzoic acid), 6-methyl-2,4-heptanediol di(m-methylbenzoic acid), 2,2,6,6-tetramethyl-3,5-heptanediol dibenzoate, 4-methyl-3,5-octanediol dibenzoate, 4-ethyl-3,5-octanediol dibenzoate, 4-propyl-3,5-octanediol dibenzoate, 4-butyl-3,5-octanediol dibenzoate, 4,4-dimethyl-3,5-octanediol dibenzoate, 4-methyl-4-ethyl-3,5-octanediol dibenzoate, 2-methyl-4-ethyl-3 5-Octanediol dibenzoate, 2-Methyl-6-ethyl-3,5-octanediol dibenzoate, 5-methyl-4,6-nonanediol dibenzoate, 5-ethyl-4,6-nonanediol dibenzoate, 5-propyl-4,6-nonanediol dibenzoate, 5-butyl-4,6-nonanediol dibenzoate, 5,5-dimethyl-4,6-nonanediol dibenzoate, 5-methyl-4-ethyl-4,6-nonanediol dibenzoate, 5-phenyl-4,6-nonanediol dibenzoate, 4,6-nonanediol dibenzoate and 4-butyl-3,5-heptanediol dibenzoate, preferably: it is preferably 2,4-pentanediol dibenzoate, 2,4-pentanediol di-p-methylbenzoate, 2,4-pentanediol di-p-ethylbenzoate, 2,4-Pentanediol di-p-propylbenzoate, 2,4-Pentanediol di-p-n-butylbenzoate, 2,4-Pentanediol di-p-tert-butylbenzoate, 2,4-Pentanediol di-p-isopropylbenzoate, 3,5-Heptanediol dibenzoate, 4-Ethyl-3,5-Heptanediol dibenzoate, 3,5-Heptanediol di-p-methylbenzoate, 3,5-Heptanediol di-p-ethylbenzoate, 3,5-Heptanediol di-p-chlorobenzoate, 3,5-Heptanediol di-p-propylbenzoate, 3,5-Heptanediol di-p-isopropylbenzoate, 3,5- Heptanediol di-p-methoxybenzoate, 3,5-heptanediol di-p-n-butylbenzoate, 3,5-heptanediol di-p-tert-butylbenzoate, 2-methyl-3,5-heptanediol dibenzoate, 4-methyl-3,5-heptanediol dibenzoate, 6-methyl-3,5-heptanediol dibenzoate, 1,2-phenylene dibenzoate, 3-methyl-5-tert-butyl-1,2-diphenylene dibenzoate, 4-tert-butyl-1,2-diphenylene dibenzoate, 4-methyl-1,2-diphenylene dibenzoate, etc.

[0019] The solid catalyst component of the present invention comprises titanium compounds, magnesium compounds, and reaction products selected from compounds having the above general formula I.

[0020] The magnesium compound is selected from magnesium dihalides, magnesium alkoxy compounds, alkyl magnesium compounds, hydrates or alcohols of magnesium dihalides, and derivatives of magnesium dihalides in which one halogen atom in the molecular formula is replaced by a hydrocarbon oxygen or a halohydroxyl oxygen; preferably magnesium dihalides or alcohols of magnesium dihalides. Specific examples include magnesium dichloride, magnesium dibromide, magnesium diiodide, and their alcohols.

[0021] The titanium compound used can be of the general formula TiX. m (OR 1) 4-m Compounds, where R 1 For C1~C 20 The hydrocarbon group, where X is a halogen, and 1 ≤ m ≤ 4. Examples include titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, titanium tetrabutoxy, titanium tetraethoxy, titanium monochlorotriethoxy, titanium dichlorodiethoxy, and titanium trichloromonoethoxy, with titanium tetrachloride being preferred.

[0022] The cocatalyst is an alkylaluminum compound with the general formula R. m R' n AlX 3-m-n Where R and R' are selected from hydrogen, C1-C 20 Alkyl group; X is a halogen, m is selected from 0, 1, 2 or 3, and n is selected from 0, 1, 2 or 3.

[0023] The external electron donor is selected from organosiloxanes.

[0024] This invention selects one or more α-olefins with carbon chain lengths of C5 to C22 as polymerization monomers, and uses a supported, highly active Ziegler-Natta catalyst containing a special internal electron donor, in conjunction with alkyl aluminum and an external electron donor organosiloxane, to form a highly efficient catalytic system to catalyze the polymerization of olefin monomers and synthesize α-olefin polymers at low temperature and ambient pressure.

[0025] Because the co-catalyst alkylaluminum alkylates the main catalyst through ligand exchange, forming catalytically active centers, the catalyst is difficult to coordinate and complex when the n(Al) / n(Ti) ratio is very small. When the n(Al) / n(Ti) ratio is large, excess alkylaluminum will reduce tetravalent titanium to inactive divalent titanium. Only when the n(Al) / n(Ti) ratio is appropriate can high molecular weight poly-α-olefins be obtained. Similarly, silanes, as external electron donors, affect the isotacticity, molecular weight, and chain structure of the polymer. When the n(Al) / n(Si) ratio decreases, the conversion rate of α-olefins also decreases, and the molecular weight of the polymer first increases and then decreases as the n(Al) / n(Si) ratio decreases. Generally, the molar ratio of the components in the catalyst system is 1:10-500:0-500 for the main catalyst (based on titanium):co-catalyst (based on aluminum):external electron donor (based on silicon), preferably 1:20-200:0.1-100.

[0026] Due to the small particle size of the catalyst used, the average particle size of the obtained polyalphaolefin is less than 500 μm. The small polyalphaolefin particles generated in the reaction are suspended in inert silicone oil. After the reaction is completed, they are filtered, and the resulting white polyalphaolefin is sheared and dispersed by a high-speed shearing machine to obtain polyalphaolefin particles with smaller particle sizes. The finer the average particle size of the polyolefin, the easier it is to perform post-processing such as cryogenic pulverization and shearing, which can shorten the reaction time. The loose polyalphaolefin of this invention is easy to shear post-processing when preparing oil drag-reducing agents. In addition, the polyalphaolefin synthesized using this catalytic system can reach a weight-average molecular weight of tens of millions. After being formulated into drag-reducing agents, its drag-reducing performance was tested by an indoor loop evaluation device, and the drag reduction rate was about 50% when the dosage was 20 mg / kg.

[0027] Preferably, the organosiloxane is selected from one or more of cyclohexylmethyldimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, diisopropyldimethoxysilane, dipropyldimethoxysilane, dicyclopentyldimethoxysilane, diphenyldimethylsilane, tetraethoxysilane, and butyltrimethoxysilane.

[0028] Preferably, the alkylaluminum compound is selected from one or more of triethylaluminum, tripropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-octylaluminum, diethylaluminum hydrogen, diisobutylaluminum hydrogen, diethylaluminum chloride, diisobutylaluminum chloride, sesquiethylaluminum chloride, or diethylaluminum chloride.

[0029] More preferably, the alkylaluminum compound is selected from triethylaluminum and / or triisobutylaluminum.

[0030] Preferably, the diol ester compound is selected from 2,4-pentanediol dibenzoate, 2,4-pentanediol di-p-methylbenzoate, 2,4-pentanediol di-p-ethylbenzoate, 2,4-pentanediol di-p-propylbenzoate, 2,4-pentanediol di-p-n-butylbenzoate, 2,4-pentanediol di-p-tert-butylbenzoate, 2,4-pentanediol di-p-isopropylbenzoate, 3,5-heptanediol dibenzoate, 4-ethyl-3,5-heptanediol dibenzoate, 3,5-heptanediol di-p-methylbenzoate, 3,5-heptanediol di-p-ethylbenzoate, 3,5-heptanediol di-p-chlorobenzoate, 3,5-heptanediol di-p-chlorobenzoate, etc. Di(p-propyl) benzoate, 3,5-heptanediol di(p-isopropyl) benzoate, 3,5-heptanediol di(p-methoxy) benzoate, 3,5-heptanediol di(p-n-butyl) benzoate, 3,5-heptanediol di(p-tert-butyl) benzoate, 2-methyl-3,5-heptanediol dibenzoate, 4-methyl-3,5-heptanediol dibenzoate, 6-methyl-3,5-heptanediol dibenzoate, 1,2-phenylene dibenzoate, 3-methyl-5-tert-butyl-1,2-diphenylene dibenzoate, 4-tert-butyl-1,2-diphenylene dibenzoate or 4-methyl-1,2-diphenylene dibenzoate.

[0031] Preferably, the D50 of the solid catalyst component is less than 50 μm.

[0032] Furthermore, the D50 of the solid catalyst component is less than 30 μm.

[0033] Furthermore, the D50 of the solid catalyst component is less than 20 μm.

[0034] Generally, drag-reducing agents using polyalphaolefins (PAOs) synthesized via bulk polymerization are rubber-like and typically undergo cryogenic pulverization as a post-processing step. The polymer's state has little impact on the post-processing, and the D50 of the solid catalyst can be controlled to be less than 30 μm. PAOs synthesized via solution polymerization or slurry polymerization are generally used directly in crude oil pipelines without post-processing. Larger polymer particles result in longer dissolution times or require high-speed shearing post-processing. Smaller PAO particles facilitate shearing, reducing the difficulty of shearing. Therefore, a smaller D50 for the solid catalyst is better, ideally below 15 μm. In drag-reducing agent slurries, the D50 of the polymer particles is less than 500 μm, preferably less than 250 μm. Therefore, depending on the reaction conditions, the D50 of the solid catalyst is generally required to be less than 30 μm, preferably less than 20 μm, and more preferably less than 15 μm.

[0035] The polymerization reaction described in this invention can be carried out using different polymerization methods, with solvent-based slurry polymerization being the preferred method.

[0036] Furthermore, the solvent used in the solvent slurry polymerization is methyl silicone oil and / or phenylmethyl silicone oil.

[0037] The α-olefin has the general formula CH2=CH-R3, wherein R3 is a C3~C20 alkyl group.

[0038] More preferably, R3 is a C4 to C14 alkyl group.

[0039] Generally, the higher the polymerization temperature, the faster the reaction rate, but the active centers of the catalyst are more prone to deactivation, resulting in a lower molecular weight polymer. The polymerization temperature used in this invention is -30 to 30°C, preferably -10 to 0°C.

[0040] The solid catalyst components described in this invention can be prepared by the methods listed below.

[0041] Method 1: The catalyst component is prepared according to the method disclosed in patent CN1506384. First, a complex of a magnesium compound and an organic alcohol compound is obtained, and then the catalyst component is obtained by treating it with a compound selected from those shown in general formula I and a titanium compound.

[0042] Method 2: First, dissolve the magnesium compound in a solvent system containing an organic epoxy compound, an organophosphorus compound, and an inert diluent to form a homogeneous solution. Then mix it with the titanium compound and precipitate a solid in the presence of a precipitation aid. This solid is then treated with a compound selected from general formula I to attach it to the solid. If necessary, the solid is further treated with titanium tetrahalide and an inert diluent.

[0043] Method 3: A solid catalyst component is prepared by reacting the titanium compound of the present invention, specifically TiCl4, with an adduct of the general formula MgCl2·pROH. In MgCl2·pROH, p is a number from 0.1 to 6, preferably 2 to 3.5, and R is a hydrocarbon group having 1 to 18 carbon atoms. The catalyst is then obtained by further processing the compound of general formula I with the titanium compound.

[0044] Method 4: Alternatively, magnesium dialkoxy can be added to an aromatic hydrocarbon compound and stirred to form a suspension; then treated with titanium tetrachloride and an electron donor compound to obtain the solution.

[0045] Method 5: Halogenating dialkoxymagnesium compounds such as magnesium dialkoxy or magnesium diaryloxy with TiCl4 or its aromatic solution at 80–130°C. The treatment with TiCl4 or its aromatic solution can be repeated once or multiple times, and a compound of general formula I of the present invention is added during one or more such treatments.

[0046] Method Six: The catalyst component is prepared according to the method disclosed in patent US4540679. First, magnesium alkoxide and carbon dioxide are reacted to obtain a hydrocarbon-based magnesium carbonate support. Then, a transition metal compound (preferably a tetravalent titanium compound) and the hydrocarbon-based magnesium carbonate support are reacted with an electron donor of general formula I of this invention to obtain the catalyst.

[0047] Another method for preparing solid catalyst components is to form an emulsion of magnesium compounds and electron donors in a diluent, add titanium compounds to fix it to obtain spherical solids, and then process it to obtain solid catalyst components.

[0048] In any of the above preparation methods, the desired electron donor compound I can be added either in the form of a compound or in other ways, such as by obtaining it in situ using a suitable precursor of electron donor compound I, which can be converted into the desired electron donor compound through, for example, a known chemical reaction such as esterification.

[0049] Beneficial effects:

[0050] Generally, the higher the molecular weight of polyalphaolefins, the higher the drag reduction rate of the formulated drag-reducing agent. However, the molecular weight of polyalphaolefins used in domestic drag-reducing agents is generally not high, usually below 5 million, resulting in a drag reduction rate of less than 45%. This invention uses a high-efficiency Ziegler-Natta catalyst to catalyze the polymerization of alpha-olefins, obtaining polyalphaolefins with a weight-average molecular weight approaching 10 million. The formulated drag-reducing agent exhibits excellent drag reduction performance, achieving a drag reduction efficiency of approximately 50% at a dosage of 20 mg / kg. Detailed Implementation

[0051] The technical solution of the present invention will be described in detail below through specific embodiments, but the scope of protection of the present invention is not limited to the embodiments described.

[0052] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0053] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the experimental materials used in the following examples are commercially available products.

[0054] Molecular weight testing methods:

[0055] Due to the large molecular weight of the obtained polymer, the tetrahydrofuran solution prepared according to the commonly used concentration could not pass through the filter membrane used for pretreatment before entering the gel column. Poly-α-olefin was dissolved in tetrahydrofuran to prepare a poly-α-olefin THF solution of 0.05–0.1 mg / mL, and its molecular weight was determined using gel permeation chromatography (GPC). GPC analysis was performed on a Waters e2695 with a gel column temperature of 40 °C and an eluent flow rate of 1.0 mL / min.

[0056] The D50 mentioned above refers to the particle size at which the cumulative particle size distribution percentage of a sample reaches 50%. Here, D represents the diameter of the powder particles, and D50 represents the diameter at the cumulative 50% point (or the 50% passing particle diameter). D50 is also known as the average particle size or median diameter.

[0057] The testing method of this invention is as follows:

[0058] (1) Catalyst yield % = Mass of catalyst obtained / Mass of magnesium chloride used × 100%;

[0059] (2) Titanium content in the catalyst: tested using a spectrophotometer.

[0060] Test method: ① Catalyst treatment: Weigh 10 mg of catalyst sample into a 250 ml pear-shaped separatory funnel, add 20 ml of 20% sulfuric acid solution and 24 ml of n-heptane (divided into 3 portions) for extraction. The separated inorganic phase is diluted to a 25 ml volumetric flask for Ti ion determination.

[0061] ② Sample preparation: Accurately weigh 2 ml of the prepared catalyst sample solution into a 25 ml volumetric flask, add 10 ml of 10% sulfuric acid solution and 1 ml of 3% hydrogen peroxide, dilute with deionized water to make up to volume, shake well, and use a blank reagent as a reference solution to measure the absorbance at 411 nm.

[0062] ③ Standard curve preparation: Transfer 0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 8.0, and 10.0 ml of 100 mg / L titanium standard solution into 25 ml volumetric flasks, dilute to volume with deionized water, shake well, and use a blank reagent as a reference solution to measure the absorbance at the maximum absorption wavelength. Plot the standard curve. The linear regression equation is A = 15.507651C - 0.005745 (where A is absorbance and C is concentration, unit: mg / ml).

[0063] After the sample is processed as described above, it is analyzed using a spectrophotometer. The concentration C of the sample is calculated according to the above formula, and then the Ti content is obtained.

[0064] Preparation of solid catalyst components

[0065] Example 1: Preparation of Catalyst 1

[0066] In a reactor fully purged with high-purity nitrogen, 4.8 g of magnesium chloride, 95 ml of toluene, 4 ml of epichlorohydrin, and 12.5 ml of tributyl phosphate (TBP) were added sequentially. The mixture was heated to 50°C with stirring and maintained for 2.5 hours until the solid was completely dissolved. Then, 1.4 g of phthalic anhydride was added, and the mixture was maintained for another hour. The solution was cooled to below -25°C, and 56 ml of TiCl4 was added dropwise over one hour. The temperature was slowly raised to 80°C, during which a solid gradually precipitated. 6 mmol of 3,5-heptanediol dibenzoate was added, and the temperature was maintained for one hour. After filtration, 70 ml of toluene was added, and the mixture was washed twice to obtain a solid precipitate. Then, 60 ml of toluene and 40 ml of TiCl4 were added, and the mixture was heated to 100°C and treated for two hours. The filtrate was discarded, and then another 60 ml of toluene and 40 ml of TiCl4 were added, and the mixture was heated to 100°C and treated for two hours. The filtrate was then discarded. Add 60 ml of toluene, wash three times under boiling conditions, then add 60 ml of hexane, wash twice under boiling conditions, and finally add 60 ml of hexane again, wash twice at room temperature, to obtain 3.9 g of solid catalyst component, yield 81.3%. The mass ratio of magnesium, titanium, chlorine, and internal electron donor is 1.2:63.6:190:2. The catalyst D50 is 10 μm, and the Ti content is 2.6% (w / w).

[0067] Example 2 Preparation of Catalyst 2

[0068] The preparation method was the same as for catalyst 1, except that 2,4-pentanediol di-p-propylbenzoate was used instead of 3,5-heptanediol dibenzoate. The final yield of the solid catalyst was 3.6 g, with a yield of 75%. The catalyst D50 was 9.5 μm, and the Ti content was 2.3% (w / w).

[0069] Example 3: Preparation of Catalyst 3

[0070] In a reactor fully purged with high-purity nitrogen, 4.8 g of magnesium chloride, 95 ml of toluene, 4 ml of epichlorohydrin, and 12.5 ml of tributyl phosphate (TBP) were added sequentially. The mixture was heated to 50°C with stirring and maintained for 2.5 hours until the solid completely dissolved. Then, 1.4 g of phthalic anhydride was added, and the temperature was maintained for another hour. The solution was cooled to below -25°C, and 33 ml of TiCl4 was added dropwise over one hour. The temperature was slowly raised to 80°C, during which a solid gradually precipitated. 6 mmol of 2,4-pentanediol dibenzoate was added, and the temperature was maintained for one hour. After filtration, 70 ml of toluene was added, and the mixture was washed twice to obtain a solid precipitate. Then, 60 ml of toluene and 40 ml of TiCl4 were added, and the temperature was raised to 100°C for two hours. The filtrate was discarded, and then another 60 ml of toluene and 40 ml of TiCl4 were added, and the temperature was raised to 100°C for two hours. The filtrate was then discarded. Add 60 ml of toluene, wash three times under boiling conditions, then add 60 ml of hexane, wash twice under boiling conditions, and finally add 60 ml of hexane again, wash twice at room temperature, to obtain 3.7 g of solid catalyst component, with a yield of 77.1%. The mass ratio of magnesium, titanium, chlorine, and internal electron donor is 1:11.5:37:1.5. The catalyst D50 is 11 μm, and the Ti content is 2.0% (w / w).

[0071] Example 4: Preparation of Catalyst 4

[0072] In a reactor fully purged with high-purity nitrogen, 4.8 g of magnesium chloride, 95 ml of toluene, 4 ml of epichlorohydrin, and 12.5 ml of tributyl phosphate (TBP) were added sequentially. The mixture was heated to 50°C with stirring and maintained for 2.5 hours until the solid completely dissolved. Then, 1.4 g of phthalic anhydride was added, and the temperature was maintained for another hour. The solution was cooled to below -25°C, and 230 ml of TiCl4 was added dropwise over one hour. The temperature was slowly raised to 80°C, during which a solid gradually precipitated. 11 mmol of 3,5-heptanediol di-tert-butylbenzoate was added, and the temperature was maintained for one hour. After filtration, 70 ml of toluene was added, and the mixture was washed twice to obtain a solid precipitate. Then, 60 ml of toluene and 40 ml of TiCl4 were added, and the temperature was raised to 100°C for two hours. The filtrate was discarded, and then another 60 ml of toluene and 40 ml of TiCl4 were added, and the temperature was raised to 100°C for two hours. The filtrate was then discarded. Add 60 ml of toluene, wash three times under boiling conditions, then add 60 ml of hexane, wash twice under boiling conditions, and then add 60 ml of hexane again, wash twice at room temperature, to obtain 3.6 g of solid catalyst component, yield 75%. The mass ratio of magnesium, titanium, chlorine, and internal electron donor is 1.2:100:300:5. The catalyst D50 is 9.5 μm, and the Ti content is 3.0% (w / w).

[0073] Preparation of catalyst 5 in Comparative Example 1

[0074] The preparation method was the same as for catalyst 1, except that 3,5-heptanediol dibenzoate was replaced with 9,9-dimethylmethoxyfluorene. The final yield of the solid catalyst was 4.0 g, with a yield of 83.3%. The catalyst D50 was 11 μm, and the Ti content was 2.7% (w / w).

[0075] Preparation of catalyst 6 in Comparative Example 2

[0076] The preparation method was the same as for catalyst 1, except that dibutyl phthalate was used instead of 3,5-heptanediol dibenzoate. The final solid catalyst yielded 3.8 g, with a yield of 79.2%. The catalyst D50 was 8.5 μm, and the Ti content was 2.0% (w / w).

[0077] Preparation of poly-α-olefins

[0078] Example 5

[0079] The 1L Schelk flask was baked 3–5 times and purged with high-purity nitrogen 3–4 times. Under a nitrogen atmosphere, 436.6 ml of methyl silicone oil, 88.0 ml of 1-hexene, 201.2 ml of 1-dodecene, 6.5 ml of diisopropyldimethoxysilane (diluted with n-hexane, with a volume ratio of n-hexane to diisopropyldimethoxysilane of 30:1), and 3.8 ml of a 1.1M triethylaluminum solution in n-hexane were measured using a syringe and added sequentially to the 1L Schelk flask. When the temperature dropped to -5°C, 0.0428 g of solid catalyst 1 was added to the above reaction solution using a syringe, and the reaction was carried out at -5°C for 24 h. The water content of the system was 20 ppm. After the reaction was completed, the solvent silicone oil was removed by filtration, and the product was washed with anhydrous ethanol until it was a white solid. After drying, the product weighed 188.1 g, with a conversion rate of 88.6%. The weight-average molecular weight of the obtained poly-α-olefin was 8.57 million. The molar ratio of main catalyst: co-catalyst: external electron donor is 1:180.2:47.4.

[0080] Comparative Example 3

[0081] The preparation method was the same as in Example 5, except that catalyst 1 was replaced with catalyst 5, resulting in a white solid with a polyα-olefin weight of 168.5 g and a conversion rate of 79.4%. The weight-average molecular weight was 4.12 million.

[0082] Comparative Example 4

[0083] The preparation method was the same as in Example 5. A 1L Schneider flask was baked 6–8 times and purged with high-purity nitrogen 4–6 times. The water content of the system was 10 ppm. Replacing catalyst 1 with catalyst 6 yielded a white solid, 172 g of poly-α-olefin, with a conversion rate of 81.1%. The weight-average molecular weight was 5.2 million.

[0084] Comparative Example 5

[0085] The preparation method is the same as in Example 5. The 1L Schneider flask was baked 1-2 times and purged with high-purity nitrogen 1-2 times. The water content of the system was 40 ppm. Polymerization was carried out using catalyst 1 to obtain a white solid, the poly-α-olefin weighing 184 g, with a conversion rate of 86.7%. The weight-average molecular weight was 5.25 million.

[0086] Example 6

[0087] The 1L Schelk flask was baked 3–5 times and purged with high-purity nitrogen 3–4 times. Under a nitrogen atmosphere, 557.6 ml of methyl silicone oil, 61.5 ml of 1-hexene, 167.6 ml of 1-decene, 1.8 ml of diisopropyldimethoxysilane (diluted with hexane, with a hexane to diisopropyldimethoxysilane volume ratio of 30:1), and 1.7 ml of a 1.1M triethylaluminum solution in hexane were measured using a syringe and added sequentially to the 1L Schelk flask. When the temperature dropped to -5°C, 0.0723 g of catalyst 2 was added to the above reaction solution using a syringe, and the reaction was carried out at -5°C for 24 h. The water content of the system was 18 ppm. After the reaction was completed, the solvent silicone oil was removed by filtration, and the product was washed with anhydrous ethanol until it was a white solid. After drying, the product weighed 151.8 g, with a conversion rate of 91.5%. The weight-average molecular weight of the obtained poly-α-olefin was 8.19 million. The molar ratio of main catalyst: co-catalyst: external electron donor is 1:53.9:8.7.

[0088] Example 7

[0089] The 1L Schelk flask was baked 3–5 times and purged with high-purity nitrogen 3–4 times. Under a nitrogen atmosphere, 601.5 ml of methyl silicone oil, 70.0 ml of 1-octene, 187.1 ml of 1-dodecene, 1.7 ml of dicyclopentyldimethoxysilane (diluted with hexane, with a hexane to dicyclopentyldimethoxysilane volume ratio of 30:1), and 1.3 ml of a 1.1M triisobutylaluminum solution in hexane were measured using a syringe and added sequentially to the 1L Schelk flask. When the temperature dropped to -5°C, 0.0769 g of catalyst 1 was added to the above reaction solution using a syringe, and the reaction was carried out at -5°C for 24 h. The water content of the system was 18 ppm. After the reaction was completed, the solvent silicone oil was removed by filtration, and the product was washed with anhydrous ethanol until it was a white solid. After drying, the product weighed 173.5 g, with a conversion rate of 90.4%. The weight-average molecular weight of the obtained poly-α-olefin was 10.63 million. The molar ratio of main catalyst: co-catalyst: external electron donor is 1:34.2:5.9.

[0090] Example 8

[0091] The 1L Schenlk flask was baked 3–5 times and purged with high-purity nitrogen 3–4 times. Under a nitrogen atmosphere, 476.5 ml of phenylmethyl silicone oil, 43.2 ml of 1-hexene, 51.4 ml of 1-decene, 116.4 ml of 1-dodecene, 1.8 ml of diphenyldimethylsilane (diluted with hexane, with a hexane to diphenyldimethylsilane volume ratio of 30:1) and 1.1 ml of a 1.1M tri-n-octylaluminum solution in hexane were measured using a syringe and added sequentially to the 1L Schenlk flask. When the temperature dropped to -10°C, 0.0617 g of catalyst 3 was measured using a syringe and added to the above reaction solution. The reaction was carried out at -30°C for 24 h. The water content of the system was 17 ppm. After the reaction was completed, the solvent silicone oil was removed by filtration, and the product was washed with anhydrous ethanol until it was a white solid. After drying, the product weighed 145.3 g, with a conversion rate of 93.4%. The molecular weight of the obtained poly-α-olefin was 7.62 million. The molar ratio of main catalyst: co-catalyst: external electron donor is 1:46.9:10.8.

[0092] Example 9

[0093] The 2L jacketed reactor was baked 3-5 times and purged with high-purity nitrogen 3-4 times. Under a nitrogen atmosphere, 1058.8 ml of methyl silicone oil, 96.0 ml of 1-hexene, 114.2 ml of 1-octene, 258.6 ml of 1-dodecene, 3.4 ml of diisopentyldimethoxysilane (diluted with hexane, with a volume ratio of hexane to diisopentyldimethoxysilane of 30:1), and 0.9 ml of a 1.1M triethylaluminum solution in hexane were sequentially added to the 2L reactor. When the temperature dropped to -10℃, 0.137 g of catalyst 2 was added to the above reaction solution using a syringe, and the reaction was carried out at -10℃ for 24 h. The water content of the system was 20 ppm. After the reaction was completed, the solvent silicone oil was removed by filtration, and the product was washed with anhydrous ethanol until it was a white solid. After drying, the product weighed 308.1 g, with a conversion rate of 89.9%. The molecular weight of the obtained poly-α-olefin was 8.98 million. The molar ratio of main catalyst: co-catalyst: external electron donor is 1:150.5:73.3.

[0094] Example 10

[0095] The 2L jacketed reactor was baked 3-5 times and purged with high-purity nitrogen 3-4 times. Under a nitrogen atmosphere, 1066 ml of phenylmethyl silicone oil, 94.0 ml of 1-hexene, 119.1 ml of 1-decene, 263.2 ml of 1-dodecene, 4.0 ml of tetraethoxysilane (diluted with hexane, with a hexane to tetraethoxysilane volume ratio of 30:1) and 1.2 ml of a 1.1M tri-n-butylaluminum solution in hexane were sequentially added to the 2L reactor. When the temperature stabilized at 20°C, 0.139 g of catalyst 3 was added to the above reaction solution using a syringe, and the reaction was carried out at 25°C for 3 hours. The water content of the system was 25 ppm. After the reaction, the solvent silicone oil was removed by filtration, and the product was washed with anhydrous ethanol until it was a white solid. After drying, the product weighed 246.7 g, with a conversion rate of 70.2%. The molecular weight of the obtained poly-α-olefin was 6.34 million. The molar ratio of main catalyst: co-catalyst: external electron donor is 1:22.7:10.2.

[0096] Example 11

[0097] The 2L jacketed reactor was baked 3-5 times and purged with high-purity nitrogen 3-4 times. Under a nitrogen atmosphere, 1158.2 ml of methyl silicone oil, 93.8 ml of 1-hexene, 118.3 ml of 1-decene, 264.3 ml of 1-tetradecene, 4.3 ml of phenyltriethoxysilane (diluted with hexane, hexane to phenyltriethoxysilane volume ratio 30:1) and 1.5 ml of 1.1M dichloroisobutylaluminum in hexane solution were sequentially added to the 2L reactor. When the temperature stabilized at 30°C, 0.147 g of catalyst 4 was added to the above reaction solution using a syringe, and the reaction was carried out at 30°C for 2 hours. The water content of the system was 18 ppm. After the reaction, the solvent silicone oil was removed by filtration, and the product was washed with anhydrous ethanol until it was a white solid. After drying, the product weighed 247.5 g, with a conversion rate of 69.5%. The molecular weight of the obtained poly-α-olefin was 5.56 million. The molar ratio of main catalyst: co-catalyst: external electron donor is 1:20:6.5.

[0098] Example 12

[0099] The 2L jacketed reactor was baked 3-5 times and purged with high-purity nitrogen 3-4 times. Under a nitrogen atmosphere, 1069.3 ml of methyl silicone oil, 95.0 ml of 1-octene, 104.9 ml of 1-decene, 282.0 ml of 1-dodecene, 4.3 ml of phenyltriethoxysilane (diluted with hexane, hexane to phenyltriethoxysilane volume ratio 30:1) and 1.3 ml of a 1.1M diisobutylaluminum hydrogen solution in hexane were sequentially added to the 2L reactor. When the temperature stabilized at 20°C, 0.0157 g of catalyst 1 was added to the above reaction solution using a syringe, and the reaction was carried out at 20°C for 24 h. The water content of the system was 20 ppm. After the reaction was completed, the solvent silicone oil was removed by filtration, and the product was washed with anhydrous ethanol until it was a white solid. After drying, the product weighed 260.6 g, with a conversion rate of 72.5%. The molecular weight of the obtained poly-α-olefin was 6.58 million. The molar ratio of main catalyst: co-catalyst: external electron donor is 1:200:77.5.

[0100] Example 13

[0101] The 2L jacketed reactor was baked 3–5 times and purged with high-purity nitrogen 3–4 times. Under a nitrogen atmosphere, 1048.4 ml of methyl silicone oil, 96.7 ml of 1-hexene, 103.7 ml of 1-octene, 304.6 ml of 1-tetradecene, 0.058 ml of butyltrimethoxysilane (diluted with hexane, with a hexane to butyltrimethoxysilane volume ratio of 30:1) and 1.8 ml of a 1.1M dihydrodiisobutylaluminum solution in hexane were sequentially added to the 2L reactor. Once the temperature stabilized at 0°C, 0.154 g of catalyst 4 was added to the reaction solution using a syringe, and the reaction was carried out at 0°C for 20 hours. The water content of the system was 25 ppm. After the reaction was completed, the solvent silicone oil was removed by filtration, and the product was washed with anhydrous ethanol until it was a white solid. After drying, the product weighed 309.6 g, with a conversion rate of 82.4%. The molecular weight of the obtained poly-α-olefin was 8.34 million. The molar ratio of main catalyst:co-catalyst:external electron donor was 1:20.5:0.1.

[0102] Example 14

[0103] The 2L jacketed reactor was baked 3-5 times and purged with high-purity nitrogen 3-4 times. Under a nitrogen atmosphere, 998.4 ml of phenylmethyl silicone oil, 93.8 ml of 1-hexene, 102.6 ml of 1-octene, 294.7 ml of 1-tetradecene, 8.2 ml of butyltrimethoxysilane (diluted with hexane, with a hexane to butyltrimethoxysilane volume ratio of 30:1) and 1.5 ml of a 1.1M dichloroethylaluminum solution in hexane were sequentially added to the 2L reactor. When the temperature stabilized at 10°C, 0.025 g of catalyst 1 was added to the above reaction solution using a syringe, and the reaction was carried out at 10°C for 6 hours. The water content of the system was 21 ppm. After the reaction, the solvent silicone oil was removed by filtration, and the product was washed with anhydrous ethanol until it was a white solid. After drying, the product weighed 312.7 g, with a conversion rate of 85.6%. The molecular weight of the obtained poly-α-olefin was 8.05 million. The molar ratio of main catalyst: co-catalyst: external electron donor is 1:121.3:100.

[0104] Example 15

[0105] The 2L jacketed reactor was baked 3-5 times and purged with high-purity nitrogen 3-4 times. Under a nitrogen atmosphere, 1011 ml of methyl silicone oil, 90.0 ml of 1-hexene, 100.1 ml of 1-decene, 293.0 ml of 1-dodecene, and 1.3 ml of a 1.1M diisobutylaluminum hydrogen solution in n-hexane were measured using a syringe and added sequentially to the 2L reactor. When the temperature stabilized at 10°C, 0.0157 g of catalyst 1 was added to the reaction solution using a syringe, and the reaction was carried out at 10°C for 24 hours. The water content of the system was 20 ppm. After the reaction, the solvent silicone oil was removed by filtration, and the product was washed with anhydrous ethanol until it was a white solid. After drying, the product weighed 216.2 g, with a conversion rate of 60.5%. The molecular weight of the obtained poly-α-olefin was 6.01 million. The molar ratio of main catalyst:co-catalyst:external electron donor was 1:200:0.

[0106] The poly-α-olefins prepared in Examples 5-15 and Comparative Examples 3-5 were formulated into drag-reducing agents.

[0107] The drag-reducing agent is prepared by compounding 26wt% of ultra-high molecular weight poly-α-olefin, 5wt% of methyl silicone oil, 8wt% of talc, 7wt% of isobutanol, 45wt% of isooctanol, 2wt% of diethylene glycol monoethyl ether, and 7wt% of triglycerides in accordance with the proportions of the present invention.

[0108] The drag reduction rate was measured using an indoor loop evaluation device, and the results are shown in the table below:

[0109]

[0110] The high-performance catalyst synthesized above and the optimized reaction temperature were used to carry out the polymerization reaction of α-olefins. The resulting poly-α-olefin drag-reducing agent was evaluated by an indoor loop evaluation device and its drag-reducing performance was comparable to that of imported agents (imported agent, sourced from Beijing Jindingke (agent), brand name SIL643).

[0111] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for preparing ultra-high molecular weight poly-α-olefin, characterized in that, Using several α-olefins as polymerization monomers, polymerization reactions were carried out under the action of a catalyst at -30~30℃. The α-olefin has the general formula CH2=CH-R3, wherein R3 is a C4~C14 alkyl group; The polymerization reaction is solvent slurry polymerization; The catalyst includes a main catalyst, a co-catalyst, and an external electron donor; The main catalyst is a solid catalyst component, which includes magnesium, titanium, chlorine and an internal electron donor, with a mass ratio of 1:10~100:20~400:1~5. The D50 of the solid catalyst component is less than 50 μm; The internal electron donor contains at least one of the following diol ester compounds: 2,4-pentanediol dibenzoate, 2,4-pentanediol di-p-methylbenzoate, 2,4-pentanediol di-p-ethylbenzoate, 2,4-pentanediol di-p-propylbenzoate, 2,4-pentanediol di-p-n-butylbenzoate, 2,4-pentanediol di-p-tert-butylbenzoate, 2,4-pentanediol di-p-isopropylbenzoate, 3,5-heptanediol dibenzoate, 4-ethyl-3,5-heptanediol dibenzoate, 3,5-heptanediol di-p-methylbenzoate, etc. 3,5-Heptanediol di-p-ethylbenzoate, 3,5-Heptanediol di-p-chlorobenzoate, 3,5-Heptanediol di-p-propylbenzoate, 3,5-Heptanediol di-p-isopropylbenzoate, 3,5-Heptanediol di-p-methoxybenzoate, 3,5-Heptanediol di-p-n-butylbenzoate, 3,5-Heptanediol di-p-tert-butylbenzoate, 2-methyl-3,5-Heptanediol dibenzoate, 4-methyl-3,5-Heptanediol dibenzoate, 6-methyl-3,5-Heptanediol dibenzoate; The cocatalyst is an alkylaluminum compound with the general formula R. m R' n AlX 3-m-n Where R and R' are selected from hydrogen, C1-C 20 Alkyl group; X is a halogen, m is selected from 0, 1, 2 or 3, and n is selected from 0, 1, 2 or 3; The external electron donor is selected from organosiloxanes; The molar ratio of the main catalyst (based on titanium): the co-catalyst (based on aluminum): the external electron donor (based on silicon) is 1:20-200:0.1-100.

2. The method for preparing ultra-high molecular weight poly-α-olefin according to claim 1, characterized in that, The organosiloxane is selected from one or more of cyclohexylmethyldimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, diisopropyldimethoxysilane, dipropyldimethoxysilane, dicyclopentyldimethoxysilane, diphenyldimethylsilane, tetraethoxysilane, and butyltrimethoxysilane.

3. The method for preparing ultra-high molecular weight poly-α-olefin according to claim 1, characterized in that, The alkylaluminum compound is selected from one or more of triethylaluminum, tripropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-octylaluminum, diethylaluminum hydrogen, diisobutylaluminum hydrogen, diethylaluminum chloride, diisobutylaluminum chloride, sesquiethylaluminum chloride, or diethylaluminum chloride.

4. The method for preparing ultra-high molecular weight poly-α-olefin according to claim 3, characterized in that, The alkylaluminum compound is preferably selected from triethylaluminum and / or triisobutylaluminum.

5. The method for preparing ultra-high molecular weight poly-α-olefin according to claim 1, characterized in that, The solid catalyst component has a D50 of less than 30 μm.

6. The method for preparing ultra-high molecular weight poly-α-olefin according to claim 5, characterized in that, The solid catalyst component has a D50 of less than 20 μm.

7. The method for preparing ultra-high molecular weight poly-α-olefin according to claim 1, characterized in that, The solvent used in the solvent slurry polymerization is methyl silicone oil and / or phenylmethyl silicone oil.

8. The method for preparing ultra-high molecular weight poly-α-olefin according to claim 1, characterized in that, The polymerization reaction occurs at a temperature of -10 to 0°C.

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