A method for preparing medium-viscosity lubricating oil base oil directly synthesized from Fischer-Tropsch synthetic oil

Abstract

The present invention belongs to the technical field of preparing lubricating oil base oil from α-olefins, and particularly relates to a method for preparing medium-viscosity lubricating oil base oil by using high-temperature Fischer-Tropsch synthetic oil C8-C 12 The cutting components are used as raw materials. After urea dewaxing and sulfolane deoxidation and dearomatization, the olefin content is about 80%. The catalyst consists of two parts, AlCl3 and a modified carrier. The carrier is at least one of pure silicon nanomolecular sieve, nano ZrO2, and nano TiO2. Under the conditions of reaction temperature of 20-50°C and reaction pressure of 0.1-1.0MPa, the reaction is carried out under the action of AlCl3 solid catalyst for 2-6 hours. The catalyst dosage is 3-10wt%. The obtained product is processed to obtain medium-high viscosity lubricating oil base oil. Compared with the prior art, the present invention expands the raw material range of synthetic medium-viscosity lubricating oil base oil, has a simple catalyst preparation method, a product yield of ≥70%, and a kinematic viscosity of 20-40mm at 100°C. 2 / s, viscosity index ≥130, solidification point ≤‑45℃.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparing lubricating base oil from alpha-olefins, and in particular relates to a method for preparing medium-viscosity lubricating base oil from alpha-olefins through high-temperature Fischer-Tropsch synthesis. Background Art

[0002] As society progresses and develops, environmental issues become increasingly prominent, leading to increasingly stringent requirements for the performance, stability, and service life of lubricants. Compared to traditional mineral lubricants, polyalphaolefin lubricants typically offer improved low-temperature and viscosity performance, lower volatility losses, higher thermal stability, and superior lubrication and anti-wear properties. Consequently, PAOs have become a hot topic of academic and industrial research.

[0003] Foreign companies synthesize PAO by using ethylene polymerization products C8~C 12 α-olefins (C 10 PAO synthetic oil is produced by polymerization and hydrofining (mainly using α-olefins) as raw materials. Given my country's energy structure, which is "rich in coal and short of oil," increasing coal utilization has become a key development direction. By utilizing indirect coal liquefaction technology to produce α-olefins, and then synthesizing high-quality PAO lubricants, the entire industrial chain can significantly enhance coal utilization and greatly increase social benefits. This invention primarily utilizes a high-temperature Fischer-Tropsch synthesis iron-based catalyst process to produce a medium-viscosity lubricant base oil for α-olefin synthesis.

[0004] Currently, the main catalytic systems used for synthesizing α-olefin oligomers include BF3, AlCl3, Ziegler-Natta, and metallocene catalysts. BF3 is unstable and can be affected by HF, leading to equipment corrosion. Metallocene catalysts have a single active center. While AlCl3 can produce lubricants with high viscosity indexes when catalyzing α-olefin oligomerization, it is highly corrosive, requires complex post-processing, and makes product separation difficult. To address these issues, many researchers have devoted themselves to the study of AlCl3 immobilization.

[0005] Patents CN1939590 and CN1156338 utilize a gas-phase solid-support method to introduce fresh AlCl3 into a reaction tube of alumina with mesoporous and macroporous structures under N2 support to obtain an AlCl3 solid-supported catalyst. The catalyst exhibits good catalytic activity, selectivity, and stability in the low-degree polymerization of isobutylene. Chinese patent CN10366552 uses a modified AlCl3 / Al2O3 solid-supported catalyst to catalyze the polymerization of 1-decene or 1-decene with C8-C 12 The base oil is obtained by polymerization of α-olefins, the yield of the obtained base oil is greater than 60%, and the viscosity of the base oil at 100°C is 10.0-25.0 mm2 / s, the chlorine content of the oligomer is less than 2%. Chinese patent CN102060646 discloses a method for preparing an alumina-supported aluminum chloride catalyst, which uses modified γ-alumina as a carrier to support aluminum chloride for decene polymerization, overcoming the strong corrosiveness of aluminum chloride. In addition, Chinese patent CN103305263 discloses a method for preparing an alumina-supported aluminum chloride catalyst using ethylene, isobutylene and C6-C 12 The method of synthesizing lubricating oil base oil by using γ-alumina supported copper-organic aluminum as a catalyst as a raw material, and the obtained oligomer has a viscosity of 27.8 to 42.4 mm at 100 ° C. 2 / s, viscosity index is 147~171.

[0006] As can be seen from the above, the raw materials used in synthetic lubricant base oil are mainly C6~C 12 α-olefins; in terms of products, there is little research on medium-viscosity lubricant base oils. Summary of the Invention

[0007] In view of the above technical problems, the purpose of the present invention is to provide a method for preparing a medium viscosity lubricating oil base oil, using high temperature Fischer-Tropsch synthetic oil C8-C 12 The cutting components are used as raw materials, and a medium-viscosity lubricating base oil is prepared under the action of an AlCl3 solid-supported catalyst, thereby expanding the raw material range for synthesizing medium-viscosity lubricating base oil. The preparation process is simple and the base oil yield is high.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing a medium-viscosity lubricating oil base oil comprises the following steps:

[0010] High temperature Fischer-Tropsch synthetic oil C8-C 12 The cutting components are used as raw materials, and the reaction is carried out for 2 to 6 hours under the action of AlCl3 solid catalyst at a reaction temperature of 20 to 80°C and a reaction pressure of 0.1 to 1.0 MPa. The obtained product is treated to obtain a medium-viscosity lubricating oil base oil.

[0011] In some technical solutions, the high temperature Fischer-Tropsch synthetic oil C8-C 12 Before the cutting components are used to prepare medium-viscosity lubricating oil base oil, they need to be pretreated with dehydration, deoxygenation and dearomatization. The pretreatment removal indicators are that the moisture content in the raw oil is ≤0.1%, the oxygen-containing compound content is ≤1%, and the aromatic content is ≤1%.

[0012] In some technical solutions, the loading amount of the AlCl3 immobilized catalyst is 10 to 50 wt%.

[0013] In some technical solutions, the carrier in the AlCl3 immobilized catalyst is at least one of pure silicon nanomolecular sieve, nano ZrO2, and nano TiO2.

[0014] In some technical solutions, the preparation steps of the AlCl3 immobilized catalyst include:

[0015] Add an appropriate amount of anhydrous AlCl3 into a container containing an organic solvent and stir thoroughly to dissolve;

[0016] The composite modified carrier of corresponding proportion is weighed and added into the container, and the AlCl3 immobilized catalyst is obtained after refluxing, filtering, washing and drying.

[0017] In some technical solutions, the steps of preparing the composite modified carrier include:

[0018] The hydrothermally synthesized carrier is fully stirred in an alkaline solution, and after drying and roasting, an alkali-modified carrier can be obtained; and further modified with lauric acid to finally obtain the composite modified carrier.

[0019] In some technical solutions, the preparation steps of the AlCl3 immobilized catalyst include:

[0020] The hydrothermally synthesized carrier is stirred in a 0.2-3.0 mol / L alkaline solution for 1-4 hours, dried at 110°C, and calcined at 400-600°C for 3-8 hours to obtain an alkali-modified carrier; the alkali-modified carrier and lauric acid are mixed in a mass ratio of 100:(1-10), chloroform is added as a solvent, and the mixture is refluxed for 2-6 hours, then filtered, and dried at 80-90°C for 24 hours to finally obtain the composite modified carrier;

[0021] Add 4-10g of anhydrous AlCl3 into a three-necked flask containing 100-150mL of organic solvent and stir thoroughly to dissolve;

[0022] According to the AlCl3 loading amount of 10% to 50%, a certain amount of the composite modified carrier is weighed and added into the three-necked flask, refluxed at the reflux temperature for 6 to 24 hours, filtered, washed and dried to obtain the AlCl3 immobilized catalyst.

[0023] In some technical solutions, the alkaline solution is one or more of NaHCO3, NaOH, and Na2CO3, and the concentration of the alkaline solution is 0.5 to 2 mol / L; and / or,

[0024] The mass ratio of the alkali-modified carrier to lauric acid is 100:(2-8); and / or,

[0025] The calcination temperature is 400-550°C, the calcination time is 4-6 hours, and the obtained carrier particle size is 20-40 mesh; and / or,

[0026] The organic solvent is at least one of toluene, chloroform and carbon tetrachloride; and / or,

[0027] The reflux time is 6 to 12 hours.

[0028] In some technical solutions, the medium viscosity lubricating oil base oil has a kinematic viscosity of 20 to 40 mm at 100°C. 2 / s, viscosity index ≥130, freezing point ≤-45℃.

[0029] The present invention adopts the above technical solution to have at least the following beneficial effects:

[0030] 1. This application uses high temperature Fischer-Tropsch synthetic oil C8-C 12 The cutting components are used as raw materials to prepare high-quality medium-viscosity lubricant base oil. The obtained medium-viscosity lubricant base oil has a kinematic viscosity of 20-40 mm at 100 ° C. 2 / s, viscosity index ≥130, pour point ≤-45℃;

[0031] 2. This application uses AlCl3 solid-supported catalyst to catalyze the α-olefin polymerization reaction, which has the advantages of high activity, good stability, reusability and high base oil yield;

[0032] 3. Furthermore, the present application also uses a certain concentration of alkaline solution and lauric acid to treat and modify the carrier respectively. The alkaline treatment modification can increase the pore size distribution of the nanocarrier, effectively obtain a nanocatalyst with a mesoporous distribution, facilitate the diffusion of the polymerization product, and effectively control the degree of polymerization of the product; on the other hand, the lauric acid modification treatment can increase the lipophilicity and hydrophobicity of the carrier, promote the contact degree between the immobilized catalyst and the olefin substrate during the reaction, improve the reaction activity, and enhance the reaction stability of the immobilized catalyst; in addition, the surfaces of different carriers prepared hydrothermally have rich hydroxyl groups, and AlCl3 will react with the -OH groups on the carrier surface in different forms to form a relatively stable chemical structure, thereby effectively improving the activity and stability of the prepared AlCl3 immobilized catalyst in the α-olefin polymerization reaction. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the contents of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application. The various commonly used materials used in the examples are all commercially available products.

[0034] It should be understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0035] Example 1

[0036] A method for preparing medium-viscosity lubricating oil base oil by high-temperature Fischer-Tropsch synthesis of α-olefins:

[0037] (1) Carrier pretreatment: The hydrothermally synthesized pure silicon nano-HZSM-5 molecular sieve was stirred in a 0.5 mol / L alkaline solution at 60°C for 4 h, dried at 110°C, and calcined at 500°C for 5 h to obtain an alkali-modified pure silicon nano-HZSM-5 molecular sieve; the alkali-modified carrier and lauric acid were mixed in a mass ratio of 100:8, chloroform was added as a solvent, refluxed for 2 h, then filtered, and dried at 80°C for 24 h to obtain a modified pure silicon nano-HZSM-5 molecular sieve.

[0038] (2) Immobilization with aluminum trichloride solution: 10 g of anhydrous aluminum trichloride was added to 100 ml of carbon tetrachloride and stirred thoroughly to dissolve. 15 g of modified pure silicon nano-HZSM-5 molecular sieve was added to the solution and refluxed at 80°C for 10 hours. The solution was filtered, washed with n-hexane, and dried in vacuo to obtain the modified pure silicon nano-HZSM-5 molecular sieve loaded AlCl3 catalyst.

[0039] (3) High temperature Fischer-Tropsch synthetic light oil (C8-C 12 ) to prepare lubricating oil base oil by polymerization of olefin components:

[0040] Add the pre-treated high temperature Fischer-Tropsch synthetic light oil (C8-C 12 ) 100g, 5g of the above catalyst, 35% of cyclohexane as solvent, react at a temperature of 30°C and a reaction pressure of 0.1MPa for 4 hours, stop the reaction, filter the catalyst, and obtain olefin oligomers by distillation at normal pressure and under reduced pressure.

[0041] The yield of the prepared medium viscosity lubricating oil base oil is 87% and the viscosity at 100℃ is 28mm 2 / s, viscosity at 40℃ is 210mm 2 / s, viscosity index is 171, and solidification point is -45℃.

[0042] Example 2

[0043] A method for preparing medium-viscosity lubricating oil base oil by high-temperature Fischer-Tropsch synthesis of α-olefins:

[0044] (1) Carrier pretreatment: The hydrothermally synthesized nano-ZrO2 was stirred in a 0.5 mol / L alkaline solution at 60°C for 4 h, dried at 110°C, and calcined at 500°C for 5 h; the alkali-modified carrier and lauric acid were mixed in a mass ratio of 100:3, chloroform was added as a solvent, refluxed for 8 h, then filtered, and dried at 80°C for 24 h to obtain a modified nano-ZrO2 carrier.

[0045] (2) Immobilization with aluminum trichloride solution: Add 10 g of anhydrous aluminum trichloride to 100 ml of carbon tetrachloride and stir thoroughly to dissolve. Add 15 g of modified nano-ZrO2 carrier to the solution, reflux at 80°C for 10 hours, filter, wash with n-hexane, and vacuum dry to obtain the modified nano-ZrO2-loaded AlCl3 catalyst.

[0046] (3) High temperature Fischer-Tropsch synthetic light oil (C8-C 12 ) to prepare lubricating oil base oil by polymerization of olefin components:

[0047] Add the pre-treated high temperature Fischer-Tropsch synthetic light oil (C8-C 12 ) 100g, 5g of the above catalyst, 35% of cyclohexane as solvent, react at a temperature of 30°C and a reaction pressure of 0.1MPa for 4 hours, stop the reaction, filter the catalyst, and obtain olefin oligomers by distillation at normal pressure and under reduced pressure.

[0048] The yield of the prepared medium viscosity lubricating oil base oil is 85%, and the viscosity at 100℃ is 25mm 2 / s, viscosity at 40℃ is 180mm 2 / s, viscosity index is 172, and solidification point is -50℃.

[0049] Example 3

[0050] A method for preparing medium-viscosity lubricating oil base oil by high-temperature Fischer-Tropsch synthesis of α-olefins:

[0051] (1) Carrier pretreatment: The hydrothermally synthesized nano-TiO2 was stirred in a 0.5 mol / L alkaline solution at 60°C for 4 h, dried at 110°C, and calcined at 500°C for 5 h to obtain alkali-modified nano-TiO2; the alkali-modified carrier and lauric acid were mixed in a mass ratio of 100:5, chloroform was added as a solvent, refluxed for 5 h, then filtered, and dried at 80°C for 24 h to obtain a modified nano-TiO2 carrier.

[0052] (2) Immobilization with aluminum trichloride solution: Add 10 g of anhydrous aluminum trichloride to 100 ml of carbon tetrachloride and stir thoroughly to dissolve. Add 15 g of modified nano-TiO2 to the solution and reflux at 80°C for 10 hours. Filter, wash with n-hexane, and vacuum dry to obtain the modified nano-TiO2-loaded AlCl3 catalyst.

[0053] (3) High temperature Fischer-Tropsch synthetic light oil (C8-C 12 ) to prepare lubricating oil base oil by polymerization of olefin components:

[0054] Add the pre-treated high temperature Fischer-Tropsch synthetic light oil (C8-C 12 ) 100g, 5g of the above catalyst, 35% of cyclohexane as solvent, react at a temperature of 30°C and a reaction pressure of 0.1MPa for 4 hours, stop the reaction, filter the catalyst, and obtain olefin oligomers by distillation at normal pressure and under reduced pressure.

[0055] The yield of the prepared medium viscosity lubricating oil base oil is 83%, and the viscosity at 100℃ is 32mm 2 / s, viscosity at 40℃ is 322mm 2 / s, viscosity index is 139, and solidification point is -55℃.

[0056] Example 4

[0057] A method for preparing medium-viscosity lubricating oil base oil by high-temperature Fischer-Tropsch synthesis of α-olefins:

[0058] (1) Carrier pretreatment: The hydrothermally synthesized pure silicon nano-Beta molecular sieve was stirred in a 0.5 mol / L alkaline solution at 60°C for 4 h, dried at 110°C, and calcined at 500°C for 5 h to obtain alkali-modified pure silicon nano-Beta molecular sieve; the alkali-modified carrier and lauric acid were mixed in a mass ratio of 100:4, chloroform was added as a solvent, refluxed for 6 h, then filtered, and dried at 80°C for 24 h to obtain the modified nano-Beta molecular sieve.

[0059] (2) Immobilization with aluminum trichloride solution: Add 10 g of anhydrous aluminum trichloride to 100 ml of carbon tetrachloride and stir thoroughly to dissolve. Add 15 g of modified pure silicon nano-Beta molecular sieve to the solution and reflux at 80°C for 10 hours. Filter, wash with n-hexane, and vacuum dry to obtain the modified pure silicon nano-Beta molecular sieve loaded AlCl3 catalyst.

[0060] (3) High temperature Fischer-Tropsch synthetic light oil (C8-C 12 ) to prepare lubricating oil base oil by polymerization of olefin components:

[0061] Add the pre-treated high temperature Fischer-Tropsch synthetic light oil (C8-C 12 ) 100g, 5g of the above catalyst, 35% of cyclohexane as solvent, reacted at 30°C, 0.1MPa pressure for 4 hours, stopped the reaction, filtered the catalyst, and distilled under normal pressure and reduced pressure to obtain olefin oligomers. The yield of base oil was 88%, and the viscosity at 100°C was 29mm. 2 / s, viscosity at 40℃ is 227mm2 / s, viscosity index is 166, and solidification point is -52℃.

[0062] Example 5

[0063] This comparative example is basically the same as Example 1, except that the catalyst used in this comparative example is the catalyst filtered and then dried again in Example 1. 12 ) to prepare the lubricating oil base oil by polymerization of the olefin components, the reaction time is increased to 6 hours.

[0064] Add the pre-treated high temperature Fischer-Tropsch synthetic light oil (C8-C 12 ) 100g, 5g of the above catalyst, 35% of cyclohexane as solvent, reacted at 30°C, 0.1MPa for 6 hours, stopped the reaction, filtered the catalyst, and distilled under normal pressure and reduced pressure to obtain olefin oligomers. The yield of base oil was 85%, and the viscosity at 100°C was 38mm. 2 / s, viscosity at 40℃ is 323mm 2 / s, viscosity index is 168.

[0065] From the comparison of Examples 1 and 5, it can be seen that the immobilized catalyst has good recycling performance, and as the time of the α-olefin polymerization reaction catalyzed by the AlCl3 immobilized catalyst increases, the viscosity of the prepared medium-viscosity lubricating oil base oil is significantly improved.

[0066] Comparative Example

[0067] Add the pre-treated high temperature Fischer-Tropsch synthetic light oil (C8-C 12 ) 100g, anhydrous AlCl3, 10g catalyst, cyclohexane as solvent, 35% usage, temperature 30 ° C, reaction pressure 0.1 MPa conditions for 4 hours, stop the reaction, after alkali washing and then washing with water, atmospheric distillation and vacuum distillation to obtain olefin oligomers. The base oil yield is 65%, 100 ° C viscosity of 49.25mm 2 / s, viscosity at 40℃ is 457.5mm 2 / s, viscosity index is 168.

[0068] As can be seen, the immobilized catalyst effectively enhances the catalytic activity of AlCl₃ and significantly increases base oil yield. Furthermore, it effectively controls the degree of olefin polymerization and product viscosity. Furthermore, the immobilized catalyst is recyclable, minimizing environmental pollution and effectively reducing operating costs.

[0069] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for preparing a medium-viscosity lubricating oil base oil, characterized in that: The following steps are involved: High temperature Fischer-Tropsch synthetic oil C8-C 12 The cutting component is used as a raw material and mixed with a catalyst composed of anhydrous aluminum chloride and a composite modified support for reaction for 2 to 6 hours. The composite modified support is obtained by fully stirring a hydrothermally synthesized support in an alkaline solution, drying and calcining it, and then reflux-modifying it with lauric acid. The anhydrous aluminum chloride is immobilized on the composite modified support at a concentration of 10 to 50 wt%. The polymerization is carried out under the conditions of reaction temperature of 20~50℃ and reaction pressure of 0.1~1.0MPa; The reaction product is separated by atmospheric pressure and vacuum distillation to directly obtain a medium-viscosity lubricating base oil with a kinematic viscosity of 20 to 40 mm² / s at 100°C, a viscosity index ≥130, and a pour point ≤-45°C.

2. The preparation method according to claim 1, characterized in that The high temperature Fischer-Tropsch synthetic oil C8-C 12 The cutting components need to be pretreated with dehydration, deoxygenation and dearomatization before preparing medium-viscosity lubricant base oil.

3. The preparation method according to claim 1, characterized in that The carrier in the catalyst is at least one of pure silicon nanomolecular sieve, nano ZrO2 and nano TiO2.

4. The preparation method according to claim 1, characterized in that The steps of preparing the catalyst include: Add an appropriate amount of anhydrous AlCl3 into a container containing an organic solvent and stir thoroughly to dissolve; The composite modified carrier in corresponding proportion is weighed and added into the container, and the catalyst is obtained after refluxing, filtering, washing and drying.

5. The preparation method according to claim 1, characterized in that The steps of preparing the catalyst include: The hydrothermally synthesized support was stirred in a 0.2-3.0 mol / L alkaline solution for 1-4 h, dried at 110°C, and calcined at 400-600°C for 3-8 h to obtain an alkali-modified support. The alkali-modified carrier and lauric acid are mixed in a mass ratio of 100:(1-10), chloroform is added as a solvent, refluxed for 2-6 hours, then filtered, and dried at 80-90°C for 24 hours to finally obtain a composite modified carrier; Add 4-10 g of anhydrous AlCl3 into a three-necked flask containing 100-150 mL of organic solvent and stir thoroughly to dissolve. A certain amount of the composite modified support was weighed according to an AlCl3 loading of 10% to 50% and added to the three-necked flask. The mixture was refluxed at the reflux temperature for 6 to 24 hours, and the catalyst was obtained after filtration, washing, and drying.

6. The preparation method according to claim 5, characterized in that The alkaline solution is one or more of NaHCO3, NaOH, and Na2CO3, and the concentration of the alkaline solution is 0.5-2 mol / L; and / or, The mass ratio of the alkali-modified carrier to lauric acid is 100:(2-8); and / or, The calcination temperature is 400-550°C, the calcination time is 4-6 h, and the obtained carrier particle size is 20-40 mesh; and / or, The organic solvent is at least one of toluene, chloroform and carbon tetrachloride; and / or, The reflux time is 6 to 12 h.