Metallocene compound, and preparation method therefor and use thereof

Abstract

The present invention provides a metallocene compound, and a preparation method therefor and the use thereof. The structure of the metallocene compound is as represented by formula I: (Cp-R1-OR2)2MCl2 (formula I). In formula I, M is Ti or Zr; Cp is selected from a metallocene and a derivative thereof, and indene and a derivative thereof; R1 is selected from a C2-C4 alkylene and a derivative thereof; and R2 is selected from a C1-C3 alkyl and a derivative thereof. The metallocene compound can catalyze the polymerization of ethylene and / or an α-olefin, and the preparation method therefor is simple.

Description

A metallocene compound, its preparation method and application Technical Field

[0001] This invention belongs to the fields of metallocene compounds and olefin polymerization, and specifically relates to a metallocene compound, its preparation method, and its application. Background Technology

[0002] Metallocene catalysts are a class of single-active-center organometallic complexes consisting of a transition metal or rare earth metal (especially Ti, Zr, or Hf) and at least one cyclopentadienyl ligand or its derivative. The co-catalysts are mainly methylaluminoxane (MAO) and organoboron compounds. The chemical structure of metallocene catalysts is easily tunable, allowing for the customization of polymer properties, such as controlling molecular weight and distribution, and comonomer content, through catalyst structure design.

[0003] Metallocene catalysts possess advantages such as high catalytic activity, narrow molecular weight distribution of the resulting polymers, controllable polymer structure, and customizable polymer molecules. Therefore, they have significant advantages in the synthesis of polyalphaolefin (PAO) base oils in the lubricating oil field, yielding PAO base oils with controllable compositional distribution. US8536391B2 proposes a method for synthesizing PAOs from alpha-olefins using supported metallocene catalysts. The metallocene catalytic system used includes a metallocene and a solid oxide chemically treated with electron-withdrawing anions. The resulting polyalphaolefins and PAOs have high viscosity indices and low pour points, with a Kv of 20-1200 cSt at 100°C and a pour point below 20°C. The PAOs are primarily head-to-tail bonds, offering significant application value in lubricating oils and viscosity correction. However, the product distribution is relatively broad, mainly consisting of alpha-olefins containing unsaturated double bonds and partially hydrogenated alpha-olefins. Experiments have shown that the presence of unsaturated double bonds in PAOs affects the stability of lubricating oils.

[0004] CN113046130A and CN113136254A both prepared a narrow-distribution PAO base oil using a two-step method, wherein tBuNCCH3(C6H5)(η 5 -C5H4)ZrCl2、tBuNC(CH3)2(η 5 C5H4)ZrCl2 and tBuNSi(CH3)2(η 5 Metallocene catalysts such as C5H4)ZrCl2 catalyze the oligomerization of C8-C12 α-olefins, ultimately yielding PAO base oils with narrow viscosity distribution and high viscosity index. CN113150826A uses the metallocene catalyst tBuNC(CH3)2(η 5C5H4)ZrCl2 catalyzes the oligomerization reaction of α-olefins with 8-12 carbon atoms, yielding a mixture of α-olefin oligomers, ultimately resulting in a polyalphaolefin (PAO) base oil with low viscosity and high viscosity index. These patents all employ a homogeneous metallocene catalyst system with a single active site. They utilize the advantages of high activity of metallocene catalysts, narrow molecular weight distribution of the resulting polymers, controllable polymer structure, and customizable polymer molecules to produce PAO base oils with a narrow molecular weight distribution in a two-step process. However, this preparation process is complex and lengthy.

[0005] Due to the unique stereostructure of configuration-restricted metallocene catalysts, various olefin monomers can be inserted, allowing for both homopolymerization of olefins and copolymerization of ethylene / α-olefins. CN102190687A discloses a configuration-restricted metallocene compound used for copolymerization of ethylene / 1-hexene and ethylene / 1-octene, demonstrating good copolymerization performance for α-olefins. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a metallocene compound, its preparation method, and its applications. This metallocene compound can catalyze the polymerization of ethylene and / or α-olefins, and its preparation method is simple.

[0007] To achieve the above objectives, the present invention provides a metallocene compound with the structure shown in Formula I: (Cp-R1-OR2)2MCl2 (Formula I).

[0008] In Formula I, M is Ti or Zr; Cp is selected from cadmium and its derivatives, indene and its derivatives; R1 is selected from C2-C4 alkylene and its derivatives; R2 is selected from C1-C3 alkyl and its derivatives.

[0009] According to a specific embodiment of the present invention, preferably, in Formula I, R1 is selected from C2-C3 alkylene groups; R2 is selected from C1-C2 alkyl groups.

[0010] According to a specific embodiment of the present invention, preferably, Cp is selected from cyclopentadiene, butylcyclopentadiene, tetramethylcyclopentadiene, and indene.

[0011] According to a specific embodiment of the present invention, preferably, the metallocene compound has the structure shown in Formula II: (Cp-CH2CH2OCH3)2MCl2 (Formula II);

[0012] In Formula II, M is Ti or Zr; Cp is selected from cyclopentadiene, butylcyclopentadiene, tetramethylcyclopentadiene, and indene.

[0013] The present invention also provides a method for preparing the above-mentioned metallocene compound, which includes the following steps:

[0014] (1) R2OR1OTs were prepared by reacting diol monoether with p-toluenesulfonyl chloride;

[0015] (2) The R2OR1OTs obtained in step (1) are reacted with CpNa to prepare Cp-R1OR2;

[0016] (3) React the Cp-R1OR2 obtained in step (2) with sodium to prepare NaCp-R1OR2;

[0017] (4) React the NaCp-R1OR2 obtained in step (3) with MCl4 to obtain the (Cp-R1-OR2)2MCl2.

[0018] According to a specific embodiment of the present invention, preferably, the method for preparing the metallocene compound includes the following steps:

[0019] (1) At -30℃ to -10℃, p-toluenesulfonyl chloride was added to a pyridine solution of a glycol monoether and reacted for 0.5h to 1h. Then the temperature was raised to -10℃ to 10℃ and reacted for 3h to 5h to obtain the first intermediate.

[0020] (2) Using a protective gas, the first intermediate obtained in step (1) is added to the CpNa solution at -10℃ to 10℃ and reacted for 3h-5h to obtain the second intermediate;

[0021] (3) Using a protective gas, sodium and tetrahydrofuran were mixed, and the second intermediate was added under ice bath conditions. The reaction was carried out for 12-24 hours to obtain the third intermediate.

[0022] (4) The third intermediate is reacted with MCl4 under the protection of a protective gas at -25°C to -45°C for 30-60 minutes, and then the temperature is raised to 20°C-30°C and the reaction is carried out for 12-24 hours to obtain the metallocene compound.

[0023] According to a specific embodiment of the present invention, preferably, in step (1), p-toluenesulfonyl chloride is added at -25°C to -15°C to carry out the reaction.

[0024] According to a specific embodiment of the present invention, preferably, in step (2), the first intermediate obtained in step (1) is added to the CpNa solution at -5°C to 5°C to carry out the reaction.

[0025] According to a specific embodiment of the present invention, preferably, in step (3), the reaction time is 18-24 hours.

[0026] According to a specific embodiment of the present invention, preferably, in step (1), the molar ratio of the diol monoether to p-toluenesulfonyl chloride is 1:1.0-1.1, more preferably 1:1.05-1.07.

[0027] According to a specific embodiment of the present invention, preferably, in step (2), the molar ratio of R2OR1OTs to CpNa is 1:0.9-1.0, more preferably 1:0.95.

[0028] According to a specific embodiment of the present invention, preferably, in step (3), the mass ratio of Cp-R1OR2 to sodium is 1:1.1-1.5, more preferably 1:1.3-1.4.

[0029] According to a specific embodiment of the present invention, preferably, in step (4), the molar ratio of the third intermediate to MCl4 is 2-2.5:1, more preferably 2-2.15:1.

[0030] According to a specific embodiment of the present invention, preferably, in step (4), the solution of the third intermediate is added to the solution of MCl4 at a temperature of -30°C to -40°C, or MCl4 is added to the solution of the third intermediate.

[0031] According to a specific embodiment of the present invention, preferably, the reaction time after raising the temperature to 25°C is 18-24 hours.

[0032] According to a specific embodiment of the present invention, the above preparation method includes the following specific steps:

[0033] (1) In a three-necked flask with a stirrer, add glycol monoether and pyridine in sequence, and slowly add p-toluenesulfonyl chloride at -30 to -10°C. Maintain the reaction temperature at -30 to -10°C for 30 minutes. Raise the temperature to 0°C and react for 4 hours. After standing, add water and adjust the pH to 2 with hydrochloric acid. Separate the organic phase and extract the aqueous phase with diethyl ether. Combine the organic phases and wash them in sequence with saturated sodium carbonate, saturated brine and distilled water. Dry with anhydrous magnesium sulfate. After filtration, remove low-boiling-point substances under reduced pressure to obtain the first intermediate.

[0034] (2) Under argon protection, the THF solution of CpNa was added to the reaction flask, and the first intermediate was slowly added dropwise at 0°C. After the addition was complete, the reaction was stirred for 4 hours, ice water was added, the mixture was stirred, and the layers were allowed to stand. The organic phase was separated, and the aqueous phase was extracted with diethyl ether. The organic phases were combined and washed successively with saturated NaCl aqueous solution and distilled water, and dried over anhydrous magnesium sulfate. After filtration, the fraction at 40°C / 3 mmHg was collected by vacuum distillation to obtain the second intermediate.

[0035] (3) Under argon protection, sodium wire and THF were added to the reaction flask, cooled in an ice-water bath, and the second intermediate was slowly added dropwise under stirring and argon protection. The reaction was carried out for 12-24 hours. Stirring was stopped and the mixture was allowed to stand to obtain the third intermediate.

[0036] (4) Under argon protection, the tetrahydrofuran solution of the third intermediate was added to the reaction flask, and MCl4 was slowly added dropwise at -25°C to -45°C. After the addition was completed, the mixture was stirred at -25°C to -45°C for 30 minutes, then the temperature was raised to 25°C and the reaction was carried out for 12-24 hours. A small amount of n-hexane was added for washing, and a precipitate appeared. The precipitate was filtered, the solvent was removed under vacuum, and the mixture was recrystallized from dichloromethane-n-hexane to obtain the metallocene compound.

[0037] The present invention also provides a metallocene catalytic system comprising the above-mentioned metallocene compound and a cocatalyst; the cocatalyst comprising organoaluminum.

[0038] The present invention also provides an olefin polymerization method, which uses the above-mentioned metallocene compound or the above-mentioned metallocene catalytic system for catalytic reaction, and includes the following steps: adding solvent, olefin feedstock, the metallocene compound and co-catalyst to a reaction vessel, and carrying out olefin polymerization reaction at 80-100°C.

[0039] According to a specific embodiment of the present invention, preferably, the olefin polymerization includes ethylene polymerization, ethylene-α-olefin polymerization, and α-olefin polymerization.

[0040] According to a specific embodiment of the present invention, preferably, when catalytically copolymerizing ethylene with 1-octene at room temperature and pressure (MAO can be used as the co-catalyst), the catalytic activity of the metallocene compound is ≥6.5×10⁻⁶. 5 gPE / mol M·h.

[0041] According to a specific embodiment of the present invention, preferably, when the olefin polymerization method is a 1-decene oligomerization reaction, the Al / M molar ratio in the olefin polymerization reaction system is 300-700.

[0042] The present invention also provides polyolefins prepared by the above method.

[0043] According to a specific embodiment of the present invention, preferably, when the polyolefin is a copolymer of ethylene and 1-octene, the polyolefin is subjected to... 13 C-NMR and GPC measurements showed a narrow molecular weight distribution, with a 1-octene insertion rate ≥ 4.8% mol.

[0044] According to a specific embodiment of the present invention, preferably, when the polyolefin is a 1-decene polymer product, the kinematic viscosity Kv of the polymer product at 100°C is 2.86-3.54 cSt, and the viscosity index KI is 139-159.

[0045] This invention synthesizes diacetic compounds using substituted cyclopentadiene ligands. The side chain oxygen atoms of these compounds have lone pair electron groups. When there is no steric hindrance around the central metal atom, the heteroatoms of the substituted cyclopentadiene ligands can coordinate with the metal to form a configurationally restricted structure, thereby endowing the compounds with a certain ability to catalyze the polymerization or oligomerization of ethylene and α-olefins.

[0046] The present invention has the following beneficial effects:

[0047] 1. This invention introduces different substituents onto the cyclopentadienyl ring, which can improve catalyst performance, shorten the catalyst synthesis route, increase product yield, and reduce economic costs;

[0048] 2. Wide applicability: The metallocene compounds of this invention can be widely used in the polymerization reactions of various olefins, such as ethylene polymerization, ethylene-α-olefin polymerization, or α-olefin polymerization.

[0049] 3. It can be used to prepare low-viscosity PAO base oil. Detailed Implementation

[0050] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0051] Example 1

[0052] This embodiment provides a metallocene compound (C5H4-CH2CH2OCH3)2TiCl2, which is prepared by the following steps:

[0053] (1) In a 250 mL three-necked flask with a stirrer, 15.8 mL of ethylene glycol monomethyl ether and 40 mL of pyridine were added in sequence. 42.0 g of p-toluenesulfonyl chloride was slowly added at -25 °C and the reaction was maintained at -25 °C for 30 minutes. The temperature was raised to 0 °C and the reaction was carried out for 4 hours. The reaction solution was a viscous white suspension. After standing, 50 mL of water was added and the pH was adjusted to 2 with 4 mol / L hydrochloric acid. The organic phase was separated and the aqueous phase was extracted with diethyl ether. The organic phases were combined and washed in sequence with saturated sodium carbonate, saturated brine and distilled water. The solution was dried over anhydrous magnesium sulfate. After filtration, the low-boiling-point substances were removed under reduced pressure (70 °C, 4 mmHg) to obtain 33.8 g of a slightly yellow transparent liquid CH3OCH2CH2OTs, with a yield of 75.4%.

[0054] (2) Under argon protection, a THF solution containing 0.147 mol C5H5Na was added to a 250 mL stirred reaction flask. 33.8 g CH3OCH2CH2OTs was slowly added dropwise at 0 °C. After the addition was complete, a large amount of precipitate was formed. The reaction was stirred for 4 h. 50 mL of ice water was added and stirred until the precipitate was completely dissolved. The mixture was allowed to stand and separate into layers. The organic phase was separated and the aqueous phase was extracted with diethyl ether. The organic phases were combined and washed successively with saturated NaCl aqueous solution and distilled water to obtain a yellow transparent liquid. The liquid was dried over anhydrous magnesium sulfate. After filtration and vacuum distillation, the fraction at 40 °C / 3 mmHg was collected to obtain 7.1 g of a slightly yellow transparent liquid CpCH2CH2OCH3, with a yield of 45.0%.

[0055] (3) Under argon protection, 1.5 g of sodium wire and 35 mL of THF were added to the reaction flask, and the mixture was cooled to 0 °C in an ice-water bath. Under stirring and argon protection, 8.86 mmol of CpCH2CH2OCH3 was slowly added dropwise, and the reaction was stirred for 18 hours. Stirring was stopped, and the mixture was allowed to stand to obtain the supernatant NaC5H4CH2CH2OCH3. The concentration was determined to be 0.252 mol / L, and the yield was 99.5%.

[0056] (4) Under argon protection, 10 mmol of NaC5H4CH2CH2OCH3 tetrahydrofuran solution was added to the reaction flask. 4.5 mmol of TiCl4 was slowly added dropwise at -30°C. After the addition was complete, the mixture was stirred at -30°C for 30 minutes, then the temperature was raised to 25°C and stirred for 24 hours. A small amount of n-hexane was added for washing, and a precipitate appeared. The precipitate was filtered, and the solvent was removed under vacuum to obtain a solid powder. Recrystallization from dichloromethane and n-hexane yielded 1.24 g of metallocene compound crystals, with a yield of 76%. NMR spectroscopy determined the compound to be (C5H4-CH2CH2OCH3)2TiCl2. 1 H NMR (400MHz, CDCl3): δ6.80~7.80(m,8H), 1.30~2.52(m,4H), 1.80~2.40(m,4H), 3.5~4.0(s, 6H).

[0057] Example 2

[0058] This embodiment provides a metallocene compound (C5H4-CH2CH2OCH3)2ZrCl2, which is prepared by the following steps:

[0059] (1) In a 250 mL three-necked flask with a stirrer, 15.8 mL of ethylene glycol monomethyl ether and 40 mL of pyridine were added in sequence. 42.0 g of p-toluenesulfonyl chloride was slowly added at -20 °C and the reaction was maintained at -20 °C for 30 minutes. The temperature was raised to 0 °C and the reaction was carried out for 4 hours. The reaction solution was a viscous white suspension. After standing, 50 mL of water was added and the pH was adjusted to 2 with 4 mol / L hydrochloric acid. The organic phase was separated and the aqueous phase was extracted with diethyl ether. The organic phases were combined and washed in sequence with saturated sodium carbonate, saturated brine and distilled water. The solution was dried over anhydrous magnesium sulfate. After filtration, the low-boiling-point substances were removed under reduced pressure (70 °C, 4 mmHg) to obtain 34.1 g of a slightly yellow transparent liquid CH3OCH2CH2OTs, with a yield of 76.1%.

[0060] (2) Under argon protection, a THF solution containing 0.147 mol C5H5Na was added to a 250 mL stirred reaction flask. 33.8 g CH3OCH2CH2OTs was slowly added dropwise at 0 °C. After the addition was complete, a large amount of precipitate was formed. The reaction was stirred for 4 h. 50 mL of ice water was added and stirred until the precipitate was completely dissolved. The mixture was allowed to stand and separate into layers. The organic phase was separated and the aqueous phase was extracted with diethyl ether. The organic phases were combined and washed successively with saturated NaCl aqueous solution and distilled water to obtain a yellow transparent liquid. The liquid was dried over anhydrous magnesium sulfate. After filtration and vacuum distillation, the fraction at 40 °C / 3 mmHg was collected to obtain 7.5 g of a slightly yellow transparent liquid CpCH2CH2OCH3, with a yield of 47.5%.

[0061] (3) Under argon protection, 1.5 g of sodium wire and 35 mL of THF were added to the reaction flask, and the mixture was cooled to 0 °C in an ice-water bath. Under stirring and argon protection, 8.86 mmol of CpCH2CH2OCH3 was slowly added dropwise, and the reaction was stirred for 20 hours. Stirring was stopped, and the mixture was allowed to stand to obtain the supernatant NaC5H4CH2CH2OCH3. The concentration was determined to be 0.252 mol / L, and the yield was 99.5%.

[0062] (4) Under argon protection, 0.7693 g (3.3 mmol) ZrCl4 was added to 6 mL of CH2Cl2 and stirred to form a white suspension. The suspension was cooled to -40 °C in a liquid nitrogen-ethanol bath. Under argon protection, 26.6 mL (6.7 mmol, 0.252 mol / L) of a standardized tetrahydrofuran solution of MeOEtCpNa was slowly added dropwise. After the addition was complete, the mixture was stirred at -40 °C for 30 minutes, then the temperature was raised to 25 °C and stirred for 24 hours. A small amount of n-hexane was added for washing, and a precipitate appeared. The precipitate was filtered, and the solvent was removed under vacuum to obtain a solid powder. Recrystallization from dichloromethane and n-hexane yielded 0.46 g of metallocene compound crystals, with a yield of 73%. The compound was confirmed by NMR as (C5H4-CH2CH2OCH3)2ZrCl2. 1H NMR (400MHz, CDCl3): δ6.53~7.96(m,8H), 1.23~2.49(m,4H), 1.96~2.40(m,4H), 3.5~4.0(s,6H).

[0063] Example 3

[0064] This embodiment provides a metallocene compound (CH3C5H3-CH2CH2CH2OCH2CH3)2ZrCl2, which is prepared by the following steps:

[0065] (1) In a 250 mL three-necked flask with a stirrer, 24.0 mL of propylene glycol monoethyl ether and 40 mL of pyridine were added in sequence. 42.0 g of p-toluenesulfonyl chloride was slowly added at -20 °C and the reaction was maintained at -20 °C for 30 minutes. The temperature was raised to 0 °C and the reaction was carried out for 4 hours. The reaction solution was a viscous white suspension. After standing, 50 mL of water was added and the pH was adjusted to 2 with 4 mol / L hydrochloric acid. The organic phase was separated and the aqueous phase was extracted with diethyl ether. The organic phases were combined and washed in sequence with saturated sodium carbonate, saturated brine and distilled water. The solution was dried over anhydrous magnesium sulfate. After filtration, the low-boiling-point substances were removed under reduced pressure (70 °C, 4 mmHg) to obtain 37.5 g of a slightly yellow transparent liquid CH3CH2OCH2CH2CH2OTs, with a yield of 74.6%.

[0066] (2) Under argon protection, 0.147 mol CH3C p A Na THF solution was added to a 250 mL stirred reaction flask. 37.9 g of CH3CH2OCH2CH2CH2OTs was slowly added dropwise at 0 °C. After the addition was complete, a large amount of precipitate formed. The reaction was stirred for 4 h. 50 mL of ice water was added, and the mixture was stirred until the precipitate dissolved completely. The mixture was allowed to stand and separate into layers. The organic phase was collected, and the aqueous phase was extracted with diethyl ether. The combined organic phases were washed successively with saturated NaCl aqueous solution and distilled water to obtain a yellow transparent liquid. The liquid was dried over anhydrous magnesium sulfate. After filtration and vacuum distillation, the fraction collected at 40 °C / 3 mmHg yielded 9.7 g of a pale yellow transparent liquid CH3C. p -CH2CH2CH2OCH2CH3, yield 46.9%;

[0067] (3) Under argon protection, add 1.5 g of sodium wire and 35 mL of THF to the reaction flask, cool to 0 °C in an ice-water bath, and slowly add 8.86 mmol of CH3C dropwise under stirring and argon protection. p -CH2CH2CH2OCH2CH3, reacted with stirring for 20 hours; stirring was stopped, and the mixture was allowed to stand to obtain the supernatant NaCH3C. p -CH2CH2CH2OCH2CH3, with a standard concentration of 0.236 mol / L and a yield of 98.3%;

[0068] (4) Under argon protection, 0.7693 g (3.3 mmol) ZrCl4 was added to 6 mL CH2Cl2 and stirred to form a white suspension. The suspension was then cooled to -40 °C in a liquid nitrogen-ethanol bath. Under argon protection, the standardized NaCH3C solution was slowly added dropwise. p A 28.4 mL solution (6.7 mmol, 0.236 mol / L) of tetrahydrofuran containing -CH2CH2CH2OCH2CH3 was added dropwise. The mixture was stirred at -40°C for 30 minutes, then the temperature was raised to 25°C and stirred for 24 hours. A small amount of n-hexane was added for washing, resulting in a precipitate. The precipitate was filtered, and the solvent was removed under vacuum to obtain a solid powder. Recrystallization from dichloromethane and n-hexane yielded 0.823 g of a metallocene compound crystal, with a yield of 74%. NMR spectroscopy confirmed the compound to be (CH3C5H3-CH2CH2CH2OCH2CH3)2ZrCl2. 1 HNMR (400MHz, CDCl3): δ6.23~6.86 (m, 6H), 1.56~2.52 (m, 12H), 3.5~4.0 (m, 4H), 0.9~1.2 (t, 6H), 0.80~1.00 (s, 6H).

[0069] Example 4

[0070] This embodiment provides a metallocene compound (C9H6-CH2CH2OCH3)2ZrCl2, which is prepared by the following steps:

[0071] (1) In a 250 mL three-necked flask with a stirrer, 15.8 mL of ethylene glycol monomethyl ether and 40 mL of pyridine were added in sequence. 42.0 g of p-toluenesulfonyl chloride was slowly added at -22 °C and the reaction was maintained at -22 °C for 30 minutes. The temperature was raised to 0 °C and the reaction was carried out for 4 hours. The reaction solution was a viscous white suspension. After standing, 50 mL of water was added and the pH was adjusted to 2 with 4 mol / L hydrochloric acid. The organic phase was separated and the aqueous phase was extracted with diethyl ether. The organic phases were combined and washed in sequence with saturated sodium carbonate, saturated brine and distilled water. The solution was dried over anhydrous magnesium sulfate. After filtration, the low-boiling-point substances were removed under reduced pressure (70 °C, 4 mmHg) to obtain 34.0 g of a slightly yellow transparent liquid CH3OCH2CH2OTs, with a yield of 75.9%.

[0072] (2) Under argon protection, a THF solution containing 0.147 mol C9H7Na was added to a 250 mL stirred reaction flask. 33.8 g of CH3OCH2CH2OTs was slowly added dropwise at 0 °C. After the addition was complete, a large amount of precipitate was formed. The reaction was stirred for 4 h. 50 mL of ice water was added and stirred until the precipitate was completely dissolved. The mixture was allowed to stand and separate into layers. The organic phase was separated and the aqueous phase was extracted with diethyl ether. The organic phases were combined and washed successively with saturated NaCl aqueous solution and distilled water to obtain a yellow transparent liquid. The liquid was dried over anhydrous magnesium sulfate. After filtration and vacuum distillation, the fraction at 40 °C / 3 mmHg was collected to obtain 10.75 g of a slightly yellow transparent liquid CpCH2CH2OCH3, with a yield of 48.5%.

[0073] (3) Under argon protection, 1.5 g of sodium wire and 35 mL of THF were added to the reaction flask and cooled to 0 °C in an ice-water bath. Under stirring and argon protection, 8.86 mmol of methoxyethyl-indene was slowly added dropwise and the reaction was stirred for 18 hours. Stirring was stopped and the mixture was allowed to stand to obtain the supernatant NaC9H6CH2CH2OCH3, with a concentration of 0.250 mol / L and a yield of 99.4%.

[0074] (4) Under argon protection, 0.781 g (3.35 mmol) ZrCl4 was added to 6 mL of CH2Cl2 and stirred to form a white suspension. The suspension was cooled to -40 °C in a liquid nitrogen-ethanol bath. Under argon protection, 26.82 mL (6.7 mmol, 0.250 mol / L) of a standardized tetrahydrofuran solution of MeOEtC9H6Na was slowly added dropwise. After the addition was complete, the mixture was stirred at -40 °C for 30 minutes, then the temperature was raised to 25 °C and stirred for 24 hours. A small amount of n-hexane was added for washing, and a precipitate appeared. The precipitate was filtered, and the solvent was removed under vacuum to obtain a solid powder. After recrystallization from dichloromethane and n-hexane, 0.513 g of metallocene compound crystals were obtained, with a yield of 68.2%. The compound was identified as (C9H6-CH2CH2OCH3)2ZrCl2. 1 H NMR (400MHz, CDCl3): δ6.80~7.83(m,12H), 1.0~2.5(m,4H), 2.33~2.59(m,4H), 3.62~3.90(s,6H).

[0075] Catalytic olefin polymerization

[0076] The following method for testing the kinematic viscosity and calculating the viscosity index of the catalytic 1-decene oligomerization product is as follows: Using a viscometer, the kinematic viscosity (symbol: KV, unit: cSt) of the product at 40℃ and 100℃ is tested respectively. The viscosity index (VI) is calculated according to ASTM D2270 using the kinematic viscosity of the oligomer at 40℃ and 100℃.

[0077] Example 5

[0078] This embodiment uses a metallocene compound (C5H4-CH2CH2OCH3)2TiCl2 to catalyze the copolymerization of ethylene and 1-octene, which includes the following steps:

[0079] Before the reaction, the reactor was preheated under vacuum to 80°C. Argon gas was then used to flush the reactor three times, and the temperature was maintained constant. The following materials were added in a glove box: 10 μmol of metallocene compound, 100 mL of toluene, 6.7 mL of MAO (aluminum-titanium ratio 670:1), and 23 mL of 1-octene. After adding the materials through the feeder, the ethylene pressure was set to 0.6 MPa. After reacting for 30 minutes, the ethylene inlet valve was closed, and the reactor was cooled by opening the cooling water. The reactor liner was removed, and the product was poured into a beaker. Hydrochloric acid-ethanol solution was added to terminate the reaction. The polymer was first repeatedly rinsed with hydrochloric acid-ethanol solution to dissolve the residual aluminum salt, then washed three times with deionized water. Finally, it was placed in a vacuum drying oven and dried at 60°C to constant weight, yielding 3.25 g of solid. The catalytic activity of the metallocene compound was calculated to be 6.5 × 10⁻⁶. 5 g / (mol·Ti·h), based on polymer 13 The C-NMR spectrum calculation showed that the 1-octene insertion rate in the copolymer was 4.84%, and the GPD test results showed Mn = 25360, Mw = 116358, and PD = 4.59.

[0080] Example 6

[0081] This embodiment uses a metallocene compound (C5H4-CH2CH2OCH3)2ZrCl2 to catalyze the copolymerization of ethylene and 1-octene, which includes the following steps:

[0082] Before the reaction, the reactor was preheated under vacuum to 80°C. Argon gas was then used to flush the reactor three times, and the temperature was maintained constant. The following materials were added in a glove box: 10 μmol of metallocene compound, 100 mL of toluene, 6.7 mL of MAO (aluminum-zirconium ratio 670:1), and 23 mL of 1-octene. After adding the materials through the feeder, the ethylene pressure was set to 0.6 MPa. After reacting for 30 minutes, the ethylene inlet valve was closed, and the reactor was cooled by opening the cooling water. The reactor liner was removed, and the product was poured into a beaker. Hydrochloric acid-ethanol solution was added to terminate the reaction. The polymer was first repeatedly rinsed with hydrochloric acid-ethanol solution to dissolve the residual aluminum salt, then washed three times with deionized water. Finally, it was placed in a vacuum drying oven and dried at 60°C to constant weight, yielding 4.80 g of solid. The catalytic activity of the metallocene compound was calculated to be 9.6 × 10⁻⁶. 5 g / (mol·Zr·h), based on polymer 13The C-NMR spectrum calculation showed that the 1-octene insertion rate in the copolymer was 5.42%, and the GPD test results showed Mn = 18953, Mw = 85937, and PD = 4.53.

[0083] Example 7

[0084] This embodiment uses a metallocene compound (C9H6-CH2CH2OCH3)2ZrCl2 to catalyze the copolymerization of ethylene and 1-octene, which includes the following steps:

[0085] Before the reaction, the reactor was preheated under vacuum to 80°C. Argon gas was then used to flush the reactor three times, and the temperature was maintained constant. The following materials were added in a glove box: 10 μmol of metallocene compound, 100 mL of toluene, 6.7 mL of MAO (aluminum-zirconium ratio 670:1), and 25 mL of 1-octene. After adding the materials through the feeder, the ethylene pressure was set to 0.6 MPa. After reacting for 30 minutes, the ethylene inlet valve was closed, and the reactor was cooled by opening the cooling water. The reactor liner was removed, and the product was poured into a beaker. Hydrochloric acid-ethanol solution was added to terminate the reaction. The polymer was first repeatedly rinsed with hydrochloric acid-ethanol solution to dissolve the residual aluminum salt, then washed three times with deionized water. Finally, it was placed in a vacuum drying oven and dried at 60°C to constant weight, yielding 4.50 g of solid. The catalytic activity of the metallocene compound was calculated to be 9.0 × 10⁻⁶. 5 g / (mol·Zr·h), based on polymer 13 The C-NMR spectrum calculation showed that the 1-octene insertion rate in the copolymer was 4.87%, and the GPD test results showed Mn = 20433, Mw = 102341, and PD = 5.01.

[0086] Example 8

[0087] This embodiment uses a metallocene compound (C5H4-CH2CH2OCH3)2ZrCl2 to catalyze the oligomerization of 1-decene, which includes the following steps:

[0088] The three-necked flask was dried and evacuated three times. 100 mL of the treated 1-decene was added to the flask, along with 4.0 mL of MAO and 5.0 mg of the metallocene compound (C5H4-CH2CH2OCH3)2ZrCl2 (aluminum-zirconium ratio of 327:1; dissolved in 5 mL of toluene 30 min prior). The mixture was heated to 80 °C and reacted for 5 hours. After the reaction was complete, 30 mL of hydrochloric acid-ethanol was added to terminate the reaction, and the mixture was stirred for 1 hour. Ethanol was removed by atmospheric distillation, and toluene and monomer were removed by vacuum distillation, yielding the 1-decene oligomer. The monomer conversion was calculated to be 73.5%. The Kv / cSt of the obtained 1-decene oligomer was 13.15 at 40 °C, 3.54 at 100 °C, and the viscosity index VI was 159.

[0089] Example 9

[0090] This embodiment uses a metallocene compound (C5H4-CH2CH2OCH3)2ZrCl2 to catalyze the oligomerization of 1-decene, which includes the following steps:

[0091] The three-necked flask was dried and evacuated three times. 100 mL of the treated 1-decene was added to the flask, along with 4.5 mL of MAO and 5.0 mg of metallocene compound (C5H4-CH2CH2OCH3)2ZrCl2 (aluminum-zirconium ratio of 367:1; dissolved in 5 mL of toluene 30 min prior). The mixture was heated to 90 °C and reacted for 6 hours. After the reaction was complete, 30 mL of hydrochloric acid-ethanol was added to terminate the reaction, and the mixture was stirred for 1 hour. Ethanol was removed by atmospheric distillation, and toluene and monomer were removed by vacuum distillation, yielding the 1-decene oligomer. The monomer conversion was calculated to be 78.4%. The obtained 1-decene oligomer had a Kv / cSt ratio of 11.25 at 40 °C, a Kv / cSt ratio of 3.16 at 100 °C, and a viscosity index (VI) of 154.

[0092] Example 10

[0093] This embodiment uses a metallocene compound (C9H6-CH2CH2OCH3)2ZrCl2 to catalyze the oligomerization of 1-decene, which includes the following steps:

[0094] The three-necked flask was dried and evacuated three times. 100 mL of the treated 1-decene was added to the flask, along with 4.0 mL of MAO and 5.0 mg of the metallocene compound (C9H6-CH2CH2OCH3)2ZrCl2 (aluminum-zirconium ratio of 406:1; dissolved in 5 mL of toluene 30 min prior). The mixture was heated to 80 °C and reacted for 5 hours. After the reaction was complete, 30 mL of hydrochloric acid-ethanol was added to terminate the reaction, and the mixture was stirred for 1 hour. Ethanol was removed by atmospheric distillation, and toluene and monomer were removed by vacuum distillation, yielding the 1-decene oligomer. The monomer conversion was calculated to be 70.2%. The obtained 1-decene oligomer had a Kv / cSt ratio of 12.47 at 40 °C, a Kv / cSt ratio of 3.36 at 100 °C, and a viscosity index (VI) of 150.

[0095] Example 11

[0096] This embodiment uses a metallocene compound (C9H6-CH2CH2OCH3)2ZrCl2 to catalyze the oligomerization of 1-decene, which includes the following steps:

[0097] The three-necked flask was dried and evacuated three times. 100 mL of the treated 1-decene was added to the flask, along with 5.0 mL of MAO and 5.0 mg of metallocene (C9H6-CH2CH2OCH3)2ZrCl2 (i.e., an aluminum-zirconium ratio of 508:1; dissolved in 5 mL of toluene 30 min prior to the reaction). The mixture was heated to 100 °C and reacted for 5 hours. After the reaction was complete, 30 mL of hydrochloric acid-ethanol was added to terminate the reaction, and the mixture was stirred for 1 hour. Ethanol was removed by atmospheric distillation, and toluene and monomer were removed by vacuum distillation, yielding the 1-decene oligomer. The monomer conversion rate was calculated to be 81.6%. The obtained 1-decene oligomer had a Kv / cSt ratio of 10.05 at 40 °C, a Kv / cSt ratio of 2.86 at 100 °C, and a viscosity index (VI) of 139.

[0098] Comparative Example 1

[0099] This comparative example is the same as Example 8, except that the oligomerization reaction conditions in this comparative example are 50°C for 5 hours.

[0100] The obtained oligomer was subjected to atmospheric distillation to remove ethanol, and vacuum distillation to remove toluene and monomer, and 1-decene oligomer was obtained. The monomer conversion rate was calculated to be 38.3%. The Kv / cSt of the obtained 1-decene oligomer was 93.10 at 40℃, 11.20 at 100℃, and the viscosity index VI was 107.

[0101] Comparative Example 2

[0102] This comparative example is the same as Example 8, except that the oligomerization reaction conditions in this comparative example are 130°C for 5 hours.

[0103] The obtained oligomer was subjected to atmospheric distillation to remove ethanol, and vacuum distillation to remove toluene and monomer, and 1-decene oligomer was obtained. The monomer conversion rate was calculated to be 92.5%. The obtained 1-decene oligomer had a Kv / cSt of 9.93 at 40℃, a Kv / cSt of 2.72 at 100℃, and a viscosity index VI of 115.

[0104] Comparative Example 3

[0105] This comparative example is the same as Example 11, except that the aluminum-zirconium ratio in the oligomerization reaction of this comparative example is 203; that is, the amount of MAO used is 2.0 ml.

[0106] The obtained oligomer was subjected to atmospheric distillation to remove ethanol, and vacuum distillation to remove toluene and monomer, and 1-decene oligomer was obtained. The monomer conversion rate was calculated to be 32.5%. The Kv / cSt of the obtained 1-decene oligomer was 101.65 at 40℃, 13.04 at 100℃, and the viscosity index VI was 125.

[0107] Comparative Example 4

[0108] This comparative example is the same as Example 11, except that the oligomerization ratio of aluminum to zirconium in this comparative example is 1160:1; that is, the amount of MAO used is 10 ml.

[0109] The obtained oligomer was subjected to atmospheric distillation to remove ethanol, and vacuum distillation to remove toluene and monomer, and 1-decene oligomer was obtained. The monomer conversion rate was calculated to be 90.7%. The obtained 1-decene oligomer had a Kv / cSt of 10.50 at 40℃, a Kv / cSt of 2.84 at 100℃, and a viscosity index VI of 119.

[0110] As can be seen from the above, the metallocene compounds of the present invention can be used in the polymerization reactions of various olefins, such as the polymerization of ethylene with α-olefins or the polymerization of α-olefins; and can be used to prepare low-viscosity PAO base oils.

Claims

1. A metallocene compound having the structure shown in Formula I: (Cp-R1-OR2)2MCl2 Formula I, In Formula I, M is Ti or Zr; Cp is selected from cadmium and its derivatives, indene and its derivatives; R1 is selected from C2-C4 alkylene and its derivatives; R2 is selected from C1-C3 alkyl and its derivatives.

2. The metallocene compound according to claim 1, wherein, In Formula I, R1 is selected from C2-C3 alkylene groups; R2 is selected from C1-C2 alkyl groups.

3. The metallocene compound according to claim 1, wherein, Cp is selected from cyclopentadiene, butylcyclopentadiene, tetramethylcyclopentadiene, and indene.

4. The metallocene compound according to claim 1, wherein, The metallocene compound has the structure shown in Formula II: (Cp-CH2CH2OCH3)2MCl2 Formula II; In Formula II, M is Ti or Zr; Cp is selected from cyclopentadiene, butylcyclopentadiene, tetramethylcyclopentadiene, and indene.

5. A method for preparing the metallocene compound according to any one of claims 1-4, comprising the following steps: (1) R2OR1OTs were prepared by reacting diol monoether with p-toluenesulfonyl chloride; (2) The R2OR1OTs obtained in step (1) are reacted with CpNa to prepare Cp-R1OR2; (3) React the Cp-R1OR2 obtained in step (2) with sodium to prepare NaCp-R1OR2; (4) React the NaCp-R1OR2 obtained in step (3) with MCl4 to obtain the (Cp-R1-OR2)2MCl2.

6. The preparation method according to claim 5, wherein, The method for preparing the metallocene compound includes the following steps: (1) At -30℃ to -10℃, p-toluenesulfonyl chloride was added to a pyridine solution of a glycol monoether and reacted for 0.5h to 1h. Then the temperature was raised to -10℃ to 10℃ and reacted for 3h to 5h to obtain the first intermediate. (2) Using a protective gas, the first intermediate obtained in step (1) is added to the CpNa solution at -10℃ to 10℃ and reacted for 3h-5h to obtain the second intermediate; (3) Using a protective gas, sodium and tetrahydrofuran were mixed, and the second intermediate was added under ice bath conditions. The reaction was carried out for 12-24 hours to obtain the third intermediate. (4) The third intermediate is reacted with MCl4 under the protection of a protective gas at -25°C to -45°C for 30-60 minutes, and then the temperature is raised to 20°C-30°C and the reaction is carried out for 12-24 hours to obtain the metallocene compound.

7. The preparation method according to claim 6, wherein, In step (1), p-toluenesulfonyl chloride is added at -25°C to -15°C to carry out the reaction.

8. The preparation method according to claim 6, wherein, In step (2), the first intermediate obtained in step (1) is added to the CpNa solution at -5℃ to 5℃ to carry out the reaction.

9. The preparation method according to claim 6, wherein, In step (4), the molar ratio of the third intermediate to MCl4 is 2-2.5:

1.

10. The preparation method according to claim 6, wherein, In step (4), at -30°C to -40°C, a solution of the third intermediate is added to a solution of MCl4 or MCl4 is added to a solution of the third intermediate. And / or, the reaction time after raising to 25°C is 18-24 hours.

11. A metallocene catalytic system comprising the metallocene compound and a cocatalyst as described in any one of claims 1-4; wherein the cocatalyst comprises organoaluminum.

12. An olefin polymerization method, comprising the steps of using a metallocene compound as described in any one of claims 1-4 or a metallocene catalytic system as described in claim 11 to catalyze the reaction: Solvent, olefin feedstock, metallocene compound, and co-catalyst are added to the reactor, and olefin polymerization is carried out at 80-100°C.

13. The method according to claim 12, wherein, The olefin polymerization includes ethylene polymerization, ethylene-α-olefin polymerization, and α-olefin polymerization.

14. The method according to claim 12, wherein, When catalyzing the copolymerization of ethylene and 1-octene, the catalytic activity of the metallocene compound is ≥6.5 × 10⁻⁶. 5 gPE / mol M·h.

15. The method according to claim 12, wherein, When the olefin polymerization method is a 1-decene oligomerization reaction, the Al / M molar ratio in the olefin polymerization reaction system is 300-700.

16. A polyolefin prepared by the method of any one of claims 12-15.

17. The polyolefin according to claim 16, wherein, When the polyolefin is a copolymer of ethylene and 1-octene, the 1-octene insertion rate is ≥4.8%mol.

18. The polyolefin according to claim 16, wherein, When the polyolefin is a 1-decene polymer, the kinematic viscosity Kv of the polyolefin at 100°C is 2.86-3.54 cSt, and the viscosity index KI is 139-159.