Alkylated metallocene poly-alpha-olefin compound as well as preparation method and application thereof

Abstract

The invention provides an alkylated metallocene poly-alpha-olefin compound as well as a preparation method and application thereof, the preparation method comprises the following steps: carrying out alkylation reaction on metallocene poly-alpha-olefin and triphenyl thiophosphate, after the reaction is finished, adding a neutralizing reagent to carry out acid-base neutralization reaction, and carrying out solid-liquid separation to obtain the alkylated metallocene poly-alpha-olefin compound. And distilling the filtrate to obtain the alkylated metallocene poly-alpha-olefin compound. According to the invention, triphenyl thiophosphate is used for chemical modification of high-viscosity metallocene poly-alpha-olefin, trifluoromethanesulfonic acid is used as an alkylation catalyst, unsaturated double bonds having adverse effects on oxidation stability in the high-viscosity metallocene poly-alpha-olefin are saturated, use of an expensive and dangerous hydrogenation process is avoided, and the method is suitable for industrial production. The stability is improved, and the prepared alkylated metallocene poly-alpha-olefin compound has oxidation resistance and wear resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of poly-alpha-olefin preparation, in particular to an alkylated metallocene poly-alpha-olefin compound and a preparation method and application thereof. Background Art

[0002] Metallocene polyalphaolefin (mPAO) is a synthetic lubricant base oil formed by polymerization of high carbon number alpha olefins, such as 1-hexene and 1-octene, especially 1-decene, under the action of metallocene catalysts. Due to its unique long straight alkane main chain and multi-side chain structure, it has viscosity-temperature characteristics and low-temperature fluidity that mineral oil does not have. It is currently one of the most widely used base oils in synthetic engine oils, gear oils and other industrial oils and greases. The synthetic oil prepared by it greatly expands the application range of lubricating greases under low temperature, high temperature, high load and other harsh conditions. It has excellent viscosity-temperature performance, thermal oxidation stability, lubrication and anti-wear performance and detergency, greatly prolongs the oil change period, slows down the corrosion and wear of equipment, reduces the maintenance cycle of equipment, and improves the utilization rate and service life of equipment, making it an excellent substitute for traditional lubricants. The demand for mPAO in industry is growing.

[0003] Synthetic gear oil is one of the important applications of high viscosity mPAO. With the continuous advancement of industrial technology, the continuous improvement of gear design accuracy, the development of gear transmission devices towards small size, light weight, high speed and heavy load and high efficiency, and higher requirements for the performance of gear oil. Industrial gear oil is required to have excellent oxidation stability and extreme pressure anti-wear performance to extend the oil change cycle. In order to improve the anti-oxidation and anti-wear ability of oil products, it is usually achieved by adjusting lubricant additives. The increase of these additives will increase production costs and increase the preparation process of lubricants, and will also be limited by the solubility of additives.

[0004] Therefore, it is necessary to develop a new mPAO with extreme pressure, anti-wear and antioxidant properties. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide an alkylated metallocene poly-α-olefin compound and a preparation method and use thereof, so as to solve the problems in the prior art.

[0006] To achieve the above objectives and other related objectives, the present invention is achieved through the following technical solutions.

[0007] The present invention provides a method for preparing an alkylated metallocene poly-α-olefin compound, comprising the following steps:

[0008] The metallocene poly-alpha-olefin (mPAO) is subjected to an alkylation reaction with triphenyl thiophosphate (TPPT). After the reaction is completed, a neutralizing agent is added to carry out an acid-base neutralization reaction, and the solid-liquid is separated. The filtrate is distilled to obtain an alkylated metallocene poly-alpha-olefin compound.

[0009] Preferably, the mass ratio of the metallocene poly-α-olefin mPAO to the triphenyl thiophosphate is (10-20): 1. For example, it may be (10-10.7): 1, (10.7-12): 1, (12-14): 1, (14-16): 1, (16-18): 1, (18-19.4): 1, (19.4-20): 1.

[0010] Preferably, the kinematic viscosity of the metallocene polyalphaolefin at 100°C is 20 to 1000 mm 2 / s. For example, it can be 20 to 40 mm 2 / s, 40~100mm 2 / s, 100~150mm 2 / s, 150~300mm 2 / s, 300~600mm 2 / s, 600~900mm 2 / s, 900~1000mm 2 / s.

[0011] Preferably, the reaction system of the alkylation reaction further comprises a catalyst, and the catalyst is selected from one or more of Y-type molecular sieve, activated clay, trifluoromethanesulfonic acid, p-toluenesulfonic acid, and 1-butyl-3-methylimidazolium chloroaluminate.

[0012] More preferably, the amount of the catalyst added is 0.1-6% of the total mass of the metallocene poly-α-olefin and the triphenyl thiophosphate, such as 0.1-0.5%, 0.5-0.6%, 0.6-1%, 1-1.33%, 1.33-1.5%, 1.5-2%, 2-2.62%, 2.62-3%, 3-4%, 4-5%, 5-6%, more preferably 1-4%, and even more preferably 1-3%.

[0013] Preferably, the reaction temperature of the alkylation reaction is 50-100°C, such as 50-70°C, 70-95°C, 95-100°C, and more preferably 50-95°C.

[0014] Preferably, the reaction time of the alkylation reaction is 0.5 to 24 hours, such as 0.5 to 1 hour, 1 to 2 hours, 2 to 4 hours, 4 to 6 hours, 6 to 8 hours, 8 to 12 hours, 12 to 18 hours, or 18 to 24 hours.

[0015] Preferably, the reaction atmosphere of the alkylation reaction is an inert atmosphere.

[0016] Preferably, the neutralizing agent is selected from one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, sodium bicarbonate, etc. The neutralizing agent is used to remove the catalyst in the reaction solution to generate a salt insoluble in the reaction solution.

[0017] Preferably, the reaction temperature of the acid-base neutralization reaction is 50-120°C.

[0018] Preferably, the reaction time of the acid-base neutralization reaction is 0.5 to 3 hours.

[0019] Preferably, the filtrate is subjected to extraction and liquid separation before distillation to obtain a supernatant liquid. The remaining triphenyl thiophosphate in the reaction solution is removed by extraction and liquid separation.

[0020] More preferably, the extractant is one or both of methanol and propanol.

[0021] More preferably, the volume ratio of the extractant to the filtrate is (1-5):1, and further preferably (2-3):1.

[0022] More preferably, the extraction temperature is 30-80°C.

[0023] Preferably, the distillation temperature is 80-140°C.

[0024] Preferably, the distillation method is reduced pressure distillation.

[0025] The invention also discloses the alkylated metallocene poly-alpha-olefin compound obtained by the above-mentioned preparation method.

[0026] Preferably, the kinematic viscosity of the alkylated metallocene poly-α-olefin compound at 100° C. is 40 to 300 mm 2 / s, more preferably 120 to 200 mm 2 / s.

[0027] Preferably, the sulfur content of the alkylated metallocene poly-α-olefin compound is 0.1-0.4%, more preferably 0.3-0.4%.

[0028] The invention also discloses the use of the alkylated metallocene poly-alpha-olefin compound as base oil in the field of lubricating oil.

[0029] The invention uses triphenyl thiophosphate to chemically modify high-viscosity metallocene polyalpha-olefins, uses trifluoromethanesulfonic acid as an alkylation catalyst, saturates unsaturated double bonds in high-viscosity metallocene polyalpha-olefins that have an adverse effect on oxidation stability, avoids the use of expensive and dangerous hydrogenation processes, improves stability, and the prepared alkylated metallocene polyalpha-olefin compounds have antioxidant and anti-wear properties. This dual-function special base oil gives greater flexibility to the formulation of lubricating oils, can be used as a base oil for blending, and can also be added as a special additive. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Shown are FT-IR spectra of mPAO and the alkylated metallocene poly-α-olefin compound prepared in Example 2.

[0031] Figure 2 The alkylated metallocene poly-alpha-olefin compounds prepared by mPAO and Example 2 are shown. 1 HNMR spectrum.

[0032] Figure 3 The alkylated metallocene poly-alpha-olefin compounds prepared by mPAO and Example 2 are shown. 13 CNMR spectrum.

[0033] Figure 4 The FT-IR spectra of mPAO and the alkylated metallocene poly-α-olefin compound prepared in Example 2 after 96 hours of oven oxidation test are shown. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0035] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0036] In addition, it should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before or after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified; it should also be understood that the combination connection relationship between one or more devices / apparatuses mentioned in the present invention does not exclude the existence of other devices / apparatuses before or after the combination device / apparatus or the insertion of other devices / apparatuses between these explicitly mentioned two devices / apparatuses, unless otherwise specified. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.

[0037] The reaction raw material metallocene poly α-olefin mPAO used in the examples of the present application has a kinematic viscosity of 150 mm at 100°C. 2 / s, the preparation method is as follows:

[0038] (1) Into a three-necked flask which has been evacuated and filled with high-purity nitrogen 3-4 times, 250 g of 1-octene dried with 13X molecular sieves is added, and the temperature is raised to 110°C.

[0039] (2) 4.2 mg of rac-ethylenebis(indenyl)zirconium dichloride and 9.0 mg of N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate were added to a Schlenk bottle containing 5 ml of toluene, and 2 ml of triisobutylaluminum toluene solution (1 mol / L) was added and shaken to obtain a catalyst solution.

[0040] (3) The catalyst solution was injected into 1-octene for alkylation reaction, the reaction temperature was controlled at 110°C, the reaction atmosphere was nitrogen atmosphere, and after reacting for 2 hours, the reaction solution was cooled to room temperature. 1 wt% acidic clay was added to the reaction solution and stirred for 1 hour, and then filtered to obtain a filtrate. Unreacted monomers, solvents and light fractions were removed using a molecular distiller at 210°C and 1.2 mbar vacuum to obtain unhydrogenated mPAO, and the kinematic viscosity at 100°C was 150 mm 2 / s.

[0041] Example 1

[0042] The present invention provides a specific alkylated metallocene poly-α-olefin compound, and the preparation method is as follows:

[0043] 140g mPAO, 7.2g TPPT and trifluoromethanesulfonic acid were added to a reaction bottle, the amount of catalyst trifluoromethanesulfonic acid added was 3mL, and the amount of catalyst trifluoromethanesulfonic acid added was 2.6wt% of the total mass of mPAO and TPPT. The reaction was heated to 50°C for 12h. The reaction was carried out in an inert atmosphere.

[0044] After the reaction, the reaction solution was cooled to 80°C, 2 wt% calcium oxide was added, and stirred for 1 hour. The reaction liquid was cooled to room temperature and filtered. The filtrate was extracted three times with 200 ml of methanol to remove unreacted TPPT. The extraction temperature was 55°C. After the extraction, the upper liquid was distilled under reduced pressure at 90°C and 10 mbar to obtain a yellow transparent liquid product, which was an alkylated metallocene poly-α-olefin compound.

[0045] Embodiment 2-3

[0046] This example provides a specific alkylated metallocene poly-α-olefin compound, and the preparation method is basically the same as that of Example 1, except that the alkylation reaction temperature is different, and the rest of the preparation method is the same as that of Example 1.

[0047] Specifically, the alkylation reaction temperatures of Examples 2 to 3 are 70° C. and 95° C., respectively.

[0048] The mPAO and the alkylated metallocene poly-α-olefin compound prepared in Example 2 were subjected to infrared spectrum testing. The infrared spectrum was as follows: Figure 1 shown.

[0049] mPAO and the alkylated metallocene poly-α-olefin compound prepared in Example 2 were subjected to 1 HNMR test, test spectrum as Figure 2 shown.

[0050] The alkylated metallocene poly-α-olefin compound prepared in Example 2 was subjected to 13 CNMR test, test spectrum such as Figure 3 shown.

[0051] Comparative Example 1

[0052] This comparative example is a comparative example of Example 1, and the only difference from Example 1 is that the alkylation reaction temperature is different, that is, the alkylation reaction temperature is 110° C., and the rest of the preparation method is the same as that of Example 1.

[0053] Embodiments 4 to 7

[0054] Examples 4 to 7 provide specific alkylated metallocene poly-α-olefin compounds, and the preparation method is basically the same as that of Example 1, except that the alkylation reaction temperature is 90° C., and the amount of catalyst added is different, and the amount of catalyst added in Examples 4 to 7 is 0.67%, 1.33%, 2.62%, and 4%, respectively. The rest of the preparation method is the same as that of Example 1.

[0055] Embodiments 8 to 11

[0056] Examples 8 to 11 provide specific alkylated metallocene poly-α-olefin compounds, and the preparation method is basically the same as that of Example 1, except that the alkylation reaction temperature is 90° C., and the alkylation reaction time is different, which is 2 h, 4 h, 8 h, and 12 h in Examples 8 to 11, respectively. The rest of the preparation method is the same as that of Example 1.

[0057] Example 12

[0058] The present invention provides a specific alkylated metallocene poly-α-olefin compound, which is basically prepared by the same method as in Example 1, except that the amounts of mPAO and TPPT used are 140 g and 13 g, respectively. The other preparation methods are the same as in Example 1.

[0059] Performance Test:

[0060] 1. The alkylated metallocene poly-α-olefin compounds prepared in Examples 1 to 3 and Comparative Example 1 were subjected to viscosity test and sulfur content test. The kinematic viscosity was tested at 100° C. using GB / T265-1988 “Method for determination of kinematic viscosity of petroleum products and method for calculation of dynamic viscosity”. The sulfur content was tested using ASTM D2622. The test results are shown in Table 1.

[0061] Table 1 Effect of alkylation reaction temperature on product viscosity and sulfur content

[0062]

[0063] It can be seen from Table 1 that the alkylation reaction temperature has a significant effect on the product viscosity and sulfur content. Specifically, as the alkylation reaction temperature increases, the sulfur content in the product increases from 0.302% to 0.480%, and the product viscosity increases with the increase in alkylation reaction temperature at the beginning. When the alkylation reaction temperature exceeds 70°C, the product viscosity begins to decrease. When the alkylation reaction temperature increases to 110°C, the product viscosity decreases to 138mm 2 / s, even lower than the viscosity of the raw material mPAO 150mm 2 / s. This is because as the temperature increases, the cracking reaction of mPAO gradually increases, producing smaller olefins, reducing steric hindrance, facilitating alkylation reactions, and increasing sulfur content. However, excessive cracking reactions lead to shorter molecular chains, lower viscosity, and wider molecular weight distribution of the products. Therefore, the reaction temperature should be controlled within a certain range to reduce the occurrence of cracking reactions and ensure that the product has a certain sulfur content.

[0064] 2. The viscosity and sulfur content of the alkylated metallocene poly-α-olefin compounds prepared in Examples 4 to 6 and Comparative Example 2 were tested. The test results are shown in Table 2.

[0065] Table 2 Effect of catalyst dosage on product viscosity and sulfur content

[0066]

[0067] From Table 2, it can be seen that the amount of catalyst used has a significant effect on the sulfur content and viscosity of the modified mPAO product. Specifically, the sulfur content gradually increases with the increase in the amount of catalyst used, from 0.1% to 0.426%. The viscosity of the product initially increases with the increase in the amount of catalyst used, reaching a maximum of 174 mm 2 / s, but when the catalyst dosage is higher than 2.62%, the viscosity decreases rapidly. This is because the increase in catalyst dosage can provide more B acid, which is conducive to the alkylation reaction of TPPT and mPAO, resulting in an increase in the sulfur content in the product, but the higher acidity promotes the β-scission reaction to generate smaller olefins, allowing more alkylation reactions to occur, resulting in an increase in the sulfur content of the product and a decrease in viscosity.

[0068] 3. The viscosity and sulfur content of the alkylated metallocene poly-α-olefin compounds prepared in Examples 8 to 11 were tested. The test results are shown in Table 3.

[0069] Table 3 Effect of alkylation reaction time on product viscosity and sulfur content

[0070]

[0071] It can be seen from Table 3 that after 2 hours of reaction, the sulfur content in the product reached 0.31%. As the reaction time was extended to 12 hours, the sulfur content gradually increased, with a maximum value of 0.386%. The viscosity of the product began to gradually decrease after 4 hours of reaction, indicating that a slight cracking reaction occurred during this process.

[0072] 4. The initial oxidation temperature (IOT) of the metallocene poly-α-olefin and the alkylated metallocene poly-α-olefin compounds prepared in Examples 2-3, Examples 5-6 and Comparative Example 1 was tested by differential scanning calorimetry (PDSC), and the oxygen pressure of the PDSC test cell was 3.5 MPa. The test results are shown in Table 4.

[0073] Table 4 Effect of different sulfur contents on the initial oxidation temperature of the product

[0074]

[0075] It can be seen from Table 4 that IOT increases with the increase of sulfur content, from 178°C of raw material mPAO to a maximum of 225°C. This phenomenon shows that increasing the sulfur content is beneficial to improving the antioxidant properties of the product.

[0076] 5. Oven oxidation test was performed on mPAO, A-mPAO and the alkylated metallocene poly-α-olefin compound prepared in Example 2. A-mPAO is an mPAO base oil containing 1.5 wt% TPPT prepared at room temperature (the saturated concentration of TPPT in mPAO is 1.55 wt%). The samples were subjected to accelerated oxidation treatment at 150°C with copper and iron as catalysts, and the acid value of the samples was measured every 24 hours. The test results are shown in Table 5. The acid value was tested using GB / T4945.

[0077] The infrared spectrum test was carried out on the sample after the 96h oven oxidation test. The FT-IR spectrum is shown in the figure below. Figure 4 shown.

[0078] Table 5 Acid value data of oven oxidation experiment

[0079]

[0080] As shown in Table 5, as the oxidation test continued, the acid values ​​of all samples showed an upward trend. In A-mPAO, the acid value increased significantly faster. In contrast, the acid value of the unmodified mPAO increased the fastest, while the acid value of the modified mPAO increased the slowest. After the 96h oxidation experiment, the order of acid value was: A-mPAO>mPAO>Example 2. It shows that the antioxidant properties of the alkylated metallocene polyalphaolefin compound improved by TPPT are improved, while directly adding TPPT to mPAO will reduce the antioxidant properties. This is because both mPAO and A-mPAO contain olefin double bonds, and their acid value increase rate is faster than that of Example 2, and for A-mPAO, TPPT dissolved in mPAO is easily hydrolyzed with moisture in the air to form phenol, which can trigger further oxidation reactions, so the antioxidant properties are worse than mPAO.

[0081] Figure 4 Middle, located at 1720cm -1 The newly appeared absorption peak is attributed to the vibration of the carbonyl group (C=O) produced after the oil is oxidized, and the intensity of the absorption peak is consistent with the order of the acid value of the sample.

[0082] 6. The tribological properties of mPAO, A-mPAO and the alkylated metallocene poly-α-olefin compound prepared in Example 2 were evaluated using a four-ball friction tester. The test method was: the anti-wear properties of the samples were evaluated using the SH / T 0189 method, the test temperature was 75°C, the load was 196N, and the speed was 1200rpm. The test results are shown in Table 6.

[0083] Table 6 Tribological performance test results on four-ball friction tester

[0084] sample Average friction coefficient Wear spot diameter / mm mPAO 0.095 0.624 A-mPAO 0.077 0.275 Example 2 0.066 0.225

[0085] It can be seen from Table 6 that the alkylated metallocene poly-α-olefin compound modified by TPPT has excellent anti-wear properties.

[0086] 7. The tribological properties of mPAO, A-mPAO and the alkylated metallocene poly-α-olefin compound prepared in Example 2 were tested in a point-to-surface mode using a TE77 reciprocating friction tester. The test method was: a point-to-surface contact friction test was performed at 75°C for 60 minutes using a steel ball with a diameter of 8 mm and a fixed steel plate (GCr15), with a load of 392 N and a reciprocating frequency of 5 Hz. The test results are shown in Table 7.

[0087] Table 7 Tribological properties test results of samples on TE77 reciprocating friction tester

[0088]

[0089] It can be seen from Table 7 that compared with the base oil mPAO, the wear rate of A-mPAO is reduced by 25%, while the wear rate of Example 2 is greatly reduced by 72.7%. The above results all show that the alkylated metallocene poly-α-olefin compound modified by TPPT has excellent anti-wear properties, which is consistent with the results of the four-ball friction test.

[0090] 8. The extreme pressure performance of mPAO, A-mPAO and the alkylated metallocene poly-α-olefin compound prepared in Example 2 was tested using the maximum no-seizure load P in accordance with GB / T 12583-1998. B and sintering point P D , the test results are shown in Table 8.

[0091] Table 8 P of samples B and P D Comparison results

[0092]

[0093]

[0094] It can be seen from Table 8 that the extreme pressure performance of the modified alkylated metallocene polyα-olefin compound has been greatly improved. Compared with mPAO, the P B Improved by 2.5 times, P D The P of alkylated metallocene polyalphaolefin compounds was increased by 2 times compared to A-mPAO. B Improved by 1.4 times, P D It has been increased by 1.25 times, showing excellent extreme pressure performance.

[0095] 9. The kinematic viscosity, viscosity index and pour point of mPAO, A-mPAO and the alkylated metallocene poly-α-olefin compound prepared in Example 2 were tested. The test method is as follows. The test results are shown in Table 9.

[0096] Kinematic viscosity: GB / T265-1988 “Method for determination of kinematic viscosity and calculation of dynamic viscosity of petroleum products” was used to test kinematic viscosity at 100°C and 40°C.

[0097] Viscosity index: GB / T 1995.

[0098] Pour point: Pour point was determined using GB / T 3535-2006.

[0099] Table 9 Viscosity, viscosity index and pour point of samples

[0100]

[0101] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for preparing an alkylated metallocene poly-α-olefin compound, characterized in that: The method comprises the following steps: subjecting metallocene polyalpha-olefin to an alkylation reaction with triphenyl thiophosphate, adding a neutralizing agent to carry out an acid-base neutralization reaction after the reaction is completed, separating the solid from the liquid, and distilling the filtrate to obtain an alkylated metallocene polyalpha-olefin compound.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the metallocene poly-α-olefin mPAO to the triphenyl thiophosphate is (10-20):1; And / or, the kinematic viscosity of the metallocene poly-α-olefin at 100° C. is 20 to 1000 mm 2 / s.

3. The preparation method according to claim 1, characterized in that: The reaction system of the alkylation reaction also includes a catalyst, and the catalyst is selected from one or more of Y-type molecular sieve, activated clay, trifluoromethanesulfonic acid, p-toluenesulfonic acid, and 1-butyl-3-methylimidazolium chloroaluminate.

4. The preparation method according to claim 3, characterized in that: The added amount of the catalyst is 0.1-6% of the total mass of the metallocene poly-α-olefin and the triphenyl thiophosphate.

5. The preparation method according to claim 1, characterized in that: The reaction temperature of the alkylation reaction is 50 to 100°C; And / or, the reaction time of the alkylation reaction is 0.5 to 24 hours; And / or, the reaction atmosphere of the alkylation reaction is an inert atmosphere.

6. The preparation method according to claim 1, characterized in that: The neutralizing agent is selected from one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide and sodium bicarbonate; And / or, the reaction temperature of the acid-base neutralization reaction is 50-120°C; And / or, the filtrate is extracted and separated before distillation to obtain an upper liquid.

7. The preparation method according to claim 6, characterized in that: The extractant is one or both of methanol and propanol; and / or the extraction temperature is 30-80°C.

8. The alkylated metallocene poly-α-olefin compound obtained by the preparation method according to any one of claims 1 to 7.

9. The alkylated metallocene poly-α-olefin compound according to claim 8, characterized in that: The kinematic viscosity of the alkylated metallocene poly-α-olefin compound at 100° C. is 40 to 300 mm 2 / s; and / or, the sulfur content in the alkylated metallocene poly-α-olefin compound is 0.1 to 0.4 wt%.

10. Use of the alkylated metallocene poly-α-olefin compound according to any one of claims 8 to 9 as a base oil in the field of lubricating oil.

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