A metallocene catalyst composition for synthesizing low viscosity polyalphaolefins

Abstract

The application provides a metallocene catalyst composition for synthesizing low-viscosity poly-alpha-olefin. The catalyst composition is composed of quinoline-indene metallocene as a main catalyst and an organic boron reagent or an alkyl aluminum oxane reagent as a cocatalyst and application thereof. The metallocene catalyst composition claimed by the application has the advantages of low dimer content in the product, high yield of lubricating oil component and overall yield when synthesizing poly-alpha-olefin; the synthesized low-viscosity lubricating oil base oil component has excellent viscosity-temperature performance and excellent low-temperature fluidity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical industry, and particularly relates to a metallocene catalyst composition for synthesizing poly-alpha-olefin with low viscosity. BACKGROUND

[0002] PAO (poly-alpha-olefin) base oil is low in price and excellent in performance in synthetic lubricating oil. It has excellent viscosity-temperature performance, thermal stability and oxidation stability, hydrolysis stability, low corrosion and toxicity, biodegradability and other advantages, and is widely used as base oil of high-end lubricating oil. At the same time, PAO has good compatibility with mineral oil, and can also be used in semi-synthetic oil to improve the performance of lubricating oil. PAO base oil can be prepared into lubricating oil of different viscosity grades for use in different harsh environments. Generally, the 100℃ viscosity is less than or equal to 10mm 2 / s, which is called low viscosity oil, and greater than or equal to 40mm 2 / s, which is called high viscosity oil, and the viscosity between them can be called medium viscosity oil. The most widely used is low viscosity base oil, which accounts for about 90% of the total PAO consumption, mainly used in automobile engine oil, ATF liquid, hydraulic oil, military industry oil, gear oil, offshore drilling fluid, optical fiber filling oil, etc.

[0003] The catalysts for synthesizing PAO mainly include aluminum chloride catalyst, boron trifluoride catalyst, Ziegler-Nata catalyst, metallocene catalyst and ionic liquid catalyst. The metallocene catalyst has a single active center and high catalytic activity, and has become a research hotspot in recent years and has been successfully applied to industrial production. The PAO molecules synthesized by the metallocene catalyst have a unique comb-like structure and do not have straight side chains, which determines that they have higher viscosity index and better thermal stability compared with conventional PAO products.

[0004] The cocatalyst is an important part of the metallocene catalyst system, and is usually divided into two categories: alkyl aluminoxane and organoboron compound. Among them, the alkyl aluminoxane includes methyl aluminoxane, ethyl aluminoxane, butyl aluminoxane and mixtures thereof. This type of cocatalyst can only play a catalytic role when it reaches a certain proportion in the catalytic system, and the Al / Zr ratio is usually 500:1, 1000:1, 1500:1 or 2000:1. The alkyl aluminoxane is extremely active, and will react violently with water and oxygen in the air with strong heat release. Therefore, the large amount, unstable nature and high price of the alkyl aluminoxane limit its application.

[0005] The performance of PAO products is determined by the degree of polymerization and molecular weight distribution of the oligomer product. Generally speaking, the viscosity and thermal stability of the product increase with the increase of the carbon number of the PAO molecule, and more side chain structure and relatively short linear segment are beneficial to the good flowability of PAO at low temperature. By changing the composition of the catalyst system and the reaction conditions, the product distribution of the oligomerization reaction can be controlled, so as to adjust the performance of the PAO product.

[0006] For example, patent CN 105885929 discloses a method for reducing the content of dimers in the product by adding a chain shuttling agent. The method uses a metallocene as a main catalyst, an organic boride as a cocatalyst, and coal-made a-olefins as reactants, and greatly reduces the content of dimers in the polymerization product by adding a chain shuttling agent dialkyl zinc, thereby improving the yield of lubricating oil base oil components, and the obtained product has good low-temperature fluidity.

[0007] Patent US6548724 discloses a method for preparing low-viscosity metallocene poly-a-olefins by using metallocene to catalyze 1-decene. A non-bridged metallocene catalyst is used, and the synthesized low-viscosity PAO has excellent viscosity-temperature performance, but the yield of dimers in the synthesis process is as high as 49%.

[0008] Patent US8207390 discloses a method for synthesizing low-viscosity PAO by using an alkyl-substituted dicyclopentadienyl zirconium dichloride and an organic boride system to catalyze synthesis. At a certain temperature and hydrogen pressure, the viscosity of the synthesized product can reach 4.36 mm 2 / s, but the yield of dimers is as high as 47%.

[0009] In patent US8748361, a hydrogenated bridged metallocene catalyst, dimethylsilyl tetrahydroindenyl zirconium dichloride, and an organic boride catalytic system are used to synthesize low-viscosity PAO. At a temperature of 140 ℃, the viscosity of the product is 6.2 mm 2 / s, and the yield of dimers is about 38.7%, and the activity of the catalyst is about 14 Kg product / g catalyst.

[0010] In patent US2015 / 0344598, a hydrogenated vinyl-bridged metallocene catalyst, vinyl tetrahydroindenyl zirconium dichloride, and an organic boride catalytic system are used to synthesize low-viscosity PAO. At a certain hydrogen pressure, the activity of the catalyst can reach 80 Kg product / g catalyst, but about 5% of the raw material is saturated as alkanes.

[0011] Patent CN113583158 discloses a metallocene catalyst containing a dihydroinden[1,2-b]indole structure, which is used with an alkyl aluminum cocatalyst and a chain shuttling agent for synthesizing PAO. The viscosity of PAO can be adjusted by adjusting the reaction conditions or changing the type of chain shuttling agent.

[0012] The prior art synthesis of PAO requires that the raw material alpha-olefin be single or have high purity, and a large amount of dimers is produced when low viscosity PAO is synthesized, which reduces the utilization rate of raw materials and increases the cost of synthesizing PAO SUMMARY

[0013] To solve the above technical problems, the present application discloses a catalyst for synthesizing low viscosity poly-alpha-olefin using quinoline-indene metallocene catalyst and its application. The present application relates to a catalyst composition for synthesizing low viscosity poly-alpha-olefin using quinoline-indene metallocene catalyst and organic boron reagent or alkyl aluminum oxane reagent as cocatalyst, and its application. The metallocene catalyst composition claimed in the present application has the advantages of reducing the content of dimers in the product, increasing the yield of lubricating oil components and the overall yield when synthesizing poly-alpha-olefin; the synthesized low viscosity lubricating oil base oil component has excellent viscosity-temperature performance and excellent low temperature fluidity.

[0014] The present application adopts the following technical solutions:

[0015] The present application discloses a metallocene catalyst, which comprises a quinoline-indene ligand and a metal. When the quinoline-indene metallocene is used as a main catalyst and the organic boron reagent or alkyl aluminum oxane reagent is used as a cocatalyst in the catalyst system for synthesizing poly-alpha-olefin synthetic oil, the catalyst system has the advantages of high activity, low viscosity of the product, low content of dimers, high yield of the product, and adjustable viscosity of the product.

[0016] A metallocene catalyst composition for synthesizing low viscosity poly-alpha-olefin, which is composed of a main catalyst and a cocatalyst; wherein the metallocene main catalyst has the following formula I structure:

[0017]

[0018] Formula I

[0019] Wherein, M is Ti, Zr or Hf, X and X' are ligands forming δ-bond with M.

[0020] Further, X and X' are each independently selected from one of amine group, fluorine atom, bromine atom, iodine atom, chlorine atom, methyl group, ethyl group, propyl group, n-butyl group and isobutyl group.

[0021] Further, the cocatalyst is an organic boron reagent or an alkyl aluminum oxane reagent.

[0022] Further, the organoboron reagent is selected from one or more of [Ph3C][B(C6F5)4], [PhMe2NH][B(C6F5)4], B(C6F5)3; the alkylaluminoxane reagent is selected from one or more of methylaluminoxane, ethylaluminoxane, n-propylaluminoxane and n-butylaluminoxane.

[0023] Further, the molar ratio of aluminum in the cocatalyst to metal in the procatalyst is 10-1000:1; or the molar ratio of boron in the cocatalyst to metal in the procatalyst is 1-300:1.

[0024] Application: the application of the metallocene catalyst composition in the synthesis of low viscosity poly-α-olefins, specifically including: using α-olefins as raw materials, using the metallocene catalyst composition as catalyst, and performing polymerization reaction.

[0025] Further, the α-olefins are single or mixed α-olefins; the α-olefins are selected from one or more of 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene.

[0026] The advantages of the present application are:

[0027] For the first time, quinolinyl-indenyl metallocene catalyst system is used to prepare low viscosity PAO, the product has low dimer content, low pour point, high yield of lubricating oil components and high overall yield. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 NMR spectrum of quinolinyl-indenyl ligand;

[0029] Figure 2 NMR spectrum of quinolinyl-indenyl metallocene catalyst quinolinyl-indenyl zirconium dichloride. DETAILED DESCRIPTION

[0030] In order to make the above features and advantages of the present application more obvious and easy to understand, the following examples are given for detailed description. The methods of the present application are conventional methods in the art unless otherwise specified.

[0031] Example 1: Synthesis of quinolinyl-indenyl zirconium dichloride

[0032] (1) Synthesis of quinolinyl-indenyl ligand L1

[0033]

[0034] 0 oAt temperature C, 2-aminobenzaldehyde 1 (2.42 g, 20 mmol) and 2,3-dihydro-1H-inden-1-one 2 (2.64 g, 20 mmol) were added to a reaction flask, followed by 50 mL of ethanol. KOH (112 mg, 20 mmol) was dissolved in a small amount of ethanol (20 mL) and slowly added. After the addition was complete, the temperature reached 78°C. o Reflux at C for 2 hours. Reduce the mother liquor to 0. o C. The pH was adjusted to neutral with 1 mol / L hydrochloric acid solution, and the mixture was filtered to obtain a pale yellow solid. The solid was dissolved in ethyl acetate, dried over Na₂SO₄, and then crystallized from ethyl acetate / petroleum ether to obtain pure quinolinoindene ligand L1 (3.73 g, yield 86%). The NMR spectrum and the structure of the compound were in perfect agreement, confirming the successful preparation of the compound.

[0035] (2) Synthesis of Cat-1 with metallocene catalyst

[0036]

[0037] -78 o At C, a solution of n-butyllithium (0.8 ml, 2.0 mmol, hexane solvent) was slowly added dropwise to a 20 mL THF solution of quinolinoindene ligand L1 (434.0 mg, 2.0 mmol). After the addition was complete, the mixture was allowed to react overnight at room temperature. The mother liquor was then cooled to -78°C. o C. Slowly add a 10 mL solution of zirconium tetrachloride (233.0 mg, 1.0 mmol) in THF. After the addition is complete, allow the reaction to proceed overnight at room temperature. Filter and wash with hexane to obtain a brown solid metallocene catalyst, Cat-1 (106.0 mg, 18%). A distinct alkenyl hydrogen is present at 6.96 ppm, indicating product formation.

[0038] Application Example 1:

[0039] Catalyst preparation:

[0040] Weigh 19.7 mg of quinoline indene dichloride and dissolve it in 10 ml of toluene. Add 3 mL of 1.5 mol / L MAO / toluene solution (the molar ratio of aluminum in the co-catalyst to zirconium in the main catalyst is 100) and continue stirring for 30 min before use.

[0041] Synthetic polyalphaolefin products:

[0042] A 250 ml flask equipped with magnetic stirring was connected to a double manifold, evacuated to remove air in the flask, purged with high purity nitrogen 3-4 times, 60 g of 1-decene was weighed in, heated to 80°C, after 10 min, the catalyst solution prepared in advance was added, and the reaction was started. After 1 h of reaction, the reaction was terminated by injecting hydrochloric acid ethanol solution (hydrochloric acid concentration 10 wt%, hydrochloric acid ethanol volume ratio 1:9) into the flask, washed with water three times, and its composition was analyzed by chromatography, and the results are shown in Table 1.

[0043] Application Example 2:

[0044] The same as Application Example 1, except that the reaction raw material was 1-decene 30 g and 1-octene 30 g, and the data results are shown in Table 1.

[0045] Application Example 3:

[0046] The same as Application Example 1, except that the reaction raw material was 1-decene 30 g and 1-dodecene 30 g, and the data results are shown in Table 1.

[0047] Application Example 4:

[0048] The same as Application Example 1, except that the reaction raw material was 1-octene 20 g, 1-decene 20 g and 1-dodecene 20 g, and the data results are shown in Table 1.

[0049] Application Example 5:

[0050] The same as Application Example 1, except that the reaction temperature was 90 o C, and the data results are shown in Table 2.

[0051] Application Example 6:

[0052] The same as Application Example 1, except that the reaction temperature was 100 o C, and the data results are shown in Table 2.

[0053] Application Example 7:

[0054] The same as Application Example 1, except that the reaction temperature was 110 o C, and the data results are shown in Table 2.

[0055] Table 1 Polymer product composition and viscosity, pour point analysis obtained by Application Examples 1-4

[0056]

[0057] From the data in Table 1, it can be seen that the reaction raw material of poly-alpha-olefin is expanded from single 1-decene to a mixture of multiple olefins, and still high-yield low-viscosity poly-alpha-olefin can be obtained, and the yield is high, the viscosity index is high, and the product pour point is low.

[0058] Table 2: Composition and viscosity, pour point analysis of polymer products obtained in application examples 1, 5-7

[0059]

[0060] As can be seen from the data in Table 2, with the increase of polymerization temperature, the content of the dimer in the product increases, the content of the trimer and tetramer does not change significantly, the content of the pentamer and higher components decreases, and thus the kinematic viscosity and pour point of the obtained poly-alpha-olefin decrease with the increase of temperature.

[0061] The above description is only the preferred embodiment of the present application, and any equivalent changes and modifications made within the scope of the patent application of the present application shall be covered by the scope of the present application.

Claims

1. A metallocene catalyst composition for the synthesis of low viscosity polyalphaolefins, characterized in that, The metallocene catalyst composition comprises a main catalyst and a cocatalyst; The metallocene main catalyst has the following formula I structure: ； M is Ti, Zr or Hf, X, X' is a ligand forming δ-bond with M; The X, X' is independently selected from one of amine group, fluorine atom, bromine atom, iodine atom, chlorine atom, methyl, ethyl, propyl, n-butyl and isobutyl.

2. The metallocene catalyst composition according to claim 1, characterized in that, The cocatalyst is an organic boron reagent or an alkyl aluminum oxide reagent.

3. The metallocene catalyst composition of claim 2, wherein, The organic boron reagent is selected from one or more of [Ph3C][B(C6F5)4], [PhMe2NH][B(C6F5)4], B(C6F5)3.

4. The metallocene catalyst composition of claim 2, wherein, The alkyl aluminum oxide reagent is selected from one or more of methyl aluminum oxide, ethyl aluminum oxide, n-propyl aluminum oxide and n-butyl aluminum oxide.

5. The metallocene catalyst composition of claim 3, wherein, The molar ratio of boron in the cocatalyst to the metal in the main catalyst is 1-300:

1.

6. The metallocene catalyst composition of claim 4, wherein, The molar ratio of aluminum in the cocatalyst to the metal in the main catalyst is 10-1000:

1.

7. Use of the metallocene catalyst composition according to any one of claims 1 to 6 for the synthesis of low viscosity polyalphaolefins, characterized in that, The α-olefin is selected from one or a mixture of several of 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene.

8. Use according to claim 7, characterized in that, ​

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