Lubricating oil base oil and production method thereof

Abstract

The invention provides lubricant base oil and a production method thereof. The production method comprises the following steps: hydrofining raw oil, and fractionating to obtain a light component, a middle fraction and tower bottom wax; carrying out contact reaction on the middle fraction and a first isomerization catalyst, and carrying out contact reaction on tower bottom wax and a second isomerization catalyst; mixing the reaction products of the middle fraction and the tower bottom wax, carrying out refining reaction, and then carrying out fractionation cutting to obtain the lubricant base oil, the first isomerization catalyst and the second isomerization catalyst both comprise carrier particles and metal clusters containing multiple layers of ligand spherical shells, and the metal clusters are loaded on the carrier particles; the distillation range of the light component is 170-300 DEG C, the distillation range of the middle fraction is 300-500 DEG C, and the distillation range of the tower bottom wax is greater than 500 DEG C; the distillation range of the lubricant base oil is greater than 480 DEG C. The lubricant base oil provided by the invention has the characteristics of high yield, low cloud point, low condensation point and high viscosity index.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil base oil, specifically relating to a lubricating oil base oil and its production method. Background Technology

[0002] The precious metal dispersion technology of isomerization dewaxing catalysts is mainly used in the isomerization dewaxing, supplementary refining and white oil hydrogenation catalyst preparation in the hydroisomerization technology of lubricating oil. The isomerization dewaxing technology of lubricating oil is the most advanced lubricating oil base oil production technology today.

[0003] Among them, the supports for hydroisomerization catalysts are mainly SAPO-11, SAPO-31, SAPO-41, ZSM-22, ZSM-23, ZSM-48, and IZM-2 molecular sieves with one-dimensional straight-channel structures. These sieves provide acidity, pore confinement, and shape selectivity during the isomerization reaction. Their pore confinement and acidity characteristics determine the conversion ability of different feedstock molecules and the differences in product structure. ZSM-48 molecular sieves, with their larger one-dimensional circular pore size and suitable acidity, are particularly suitable for removing single-branched / double-branched isomers formed by the isomerization of long-chain n-alkanes. They are applicable to the hydroisomerization of heavy feedstocks such as Fischer-Tropsch synthetic oils, hydrocracking tail oils, and high-wax VGO to produce base oils. Therefore, using ZSM-48 molecular sieves with suitable silica-alumina ratios and grain sizes as supports to prepare lubricating oil isomerization dewaxing catalysts has high application value.

[0004] Furthermore, the active phase metal is also key to hydroisomerization technology. Metals such as Pt, Rh, and Pd are generally used to dehydrogenate or hydrogenate alkanes or alkenes. Moreover, the degree of metal dispersion determines the number of effective metal sites, the metal loading, and the hydrogenation performance of the metal, thus determining catalyst performance and production costs. The latest generation of active metal phases is metal clusters. Small metal nanoclusters with precise atomic arrangements, due to their unique electronic structure and unusual physical and chemical properties, have broad application prospects in many fields such as catalysis, chemical sensing, electronics, biolabeling, and biomedicine. Currently, progress has been made in the synthesis, separation, purification, characterization, and application research of metal nanoclusters.

[0005] The technical solution disclosed in CN115044051A involves dissolving the ligand levonorgestrel in dichloromethane, adding a methanol solution of chloroplatinic acid, then adding triethylamine, and finally adding tetrahydrothiophene gold chloride. After the reaction is complete, the clear solution is allowed to evaporate at room temperature in the dark to obtain crystals, which are then filtered, washed, and the resulting nano-alloy cluster material is obtained. However, the use of highly toxic solvents such as dichloromethane easily generates a large amount of difficult-to-treat waste liquid; furthermore, the post-processing of the product is complex, the yield is low, the cluster stability is insufficient, and the fluorescence intensity decreases significantly over time.

[0006] CN115678610A discloses a method for preparing lubricating oil base oil from Fischer-Tropsch wax. The method includes: cutting the Fischer-Tropsch wax to obtain a first fraction, a second fraction, and bottom wax; performing isomerization reactions on the first and second fractions using a first activated isomerization catalyst and a second activated isomerization catalyst, respectively, to obtain a first isomer oil and a second isomer oil; performing refining reactions on the first and second isomer oils using a first activated refining catalyst and a second activated refining catalyst, respectively, to obtain a first base oil product and a second base oil product; the preparation method of the first and second activated isomerization catalysts includes: performing a reduction reaction on the first and second isomerization catalysts to obtain a reduced first isomer catalyst and a reduced second isomer catalyst; and performing a primary activation and stabilization reaction on the reduced first and second isomer catalysts to obtain a first activated isomer catalyst and a second activated isomer catalyst. However, this method requires the use of multiple isomerization catalysts and refining catalysts, and the process is relatively complex.

[0007] CN115678602 A provides a method for processing Fischer-Tropsch wax, which involves subjecting the wax to isomerization cracking to obtain product A; subjecting product A to a first separation to obtain fractions A1, A2, A3, and A4; subjecting fraction A3 to an isomerization dewaxing to obtain product B; subjecting product B to a second separation to obtain fractions B1, B2, and base oil B3; subjecting fraction A4 to deoiling to obtain microcrystalline wax; and mixing fractions A2 and B2 to obtain diesel fuel. However, this method requires multiple fractionation processes, resulting in high energy consumption and a complex and difficult-to-control process.

[0008] Therefore, how to utilize metal clusters as the active phase of a catalyst to produce high-quality lubricating oil base oils through a convenient process still requires further investigation. Summary of the Invention

[0009] To address the aforementioned technical problems, the present invention aims to provide a lubricating oil base oil and its production method. By using a metal cluster containing a multi-layered ligand-protected spherical shell as the active phase of a heterogeneous catalyst, the catalytic performance of the heterogeneous catalyst can be improved, enabling the production of lubricating oil base oils with high yield and high viscosity index.

[0010] To achieve the above objectives, the present invention provides a method for producing a lubricating oil base oil, wherein the method includes:

[0011] (1) Hydrorefining the feedstock oil and then fractionating it to obtain light components, middle fractions and bottom wax;

[0012] (2) The middle fraction is brought into contact with the first isomeric catalyst and reacted, and the bottom wax is brought into contact with the second isomeric catalyst and reacted;

[0013] (3) After mixing the reaction products of the middle fraction and the bottom wax of the tower, a refining reaction is carried out, and then the mixture is fractionated to obtain the lubricating oil base oil.

[0014] Wherein, both the first and second isomer catalysts include support particles and metal clusters containing multilayer ligand shells, the metal clusters being loaded on the support particles; the distillation range of the light component is 170-300℃, the distillation range of the middle fraction is 300-500℃, and the distillation range of the bottom wax is >500℃; in step (3), the distillation range of the lubricating oil base oil is >480℃.

[0015] According to a specific embodiment of the present invention, preferably, the method for preparing the metal cluster containing multilayered ligand shells includes:

[0016] (a) Dissolve a metal compound in a mixture containing water, alcohol and ligand, and mix to obtain a metal precursor solution;

[0017] (b) Add solvent, protective agent and reducing agent to the metal precursor solution and mix. After concentration and stirring, add solvent. Repeat the concentration, stirring and solvent addition operations to obtain metal clusters containing multilayer ligand shells.

[0018] According to a specific embodiment of the present invention, preferably, the molar ratio of the ligand to the metal compound is (6-18):1, more preferably 12:1; the molar ratio of the metal compound is calculated in terms of metal elements.

[0019] According to a specific embodiment of the present invention, preferably, the molar ratio of the metal compound to the protective agent is 1:10 to 1:100, more preferably 1:15 to 1:95, further preferably 1:30 to 1:75, and even more preferably 1:40 to 1:60.

[0020] According to a specific embodiment of the present invention, preferably, in terms of the number of electrons, the ratio of the number of electrons lost by the metal to the number of electrons gained by the reducing agent in the metal compound is 1:1 to 1:10, more preferably 1:2 to 1:9.

[0021] In some specific implementations, preferably, in step (a), the mixing conditions are mixing at 30-60°C for 2-6 hours.

[0022] In some specific embodiments, preferably, in step (b), the concentration process is to concentrate the reaction solution to 10%-50% of its original volume, more preferably 20%-40%; this process can be carried out using a rotary evaporator.

[0023] In some specific embodiments, preferably, in step (b), the stirring conditions are stirring at a speed of 100-500 rpm for 6-24 hours; more preferably, the stirring conditions are stirring at a speed of 150-450 rpm for 8-20 hours.

[0024] In some specific embodiments, preferably, in step (b), the amount of solvent added is 80%-100% of the original volume, more preferably 100%.

[0025] In some specific implementations, preferably, in step (b), the operations of concentration, stirring and adding solvent are repeated 1-10 times, more preferably 2-8 times.

[0026] In some specific embodiments, preferably, the solvent includes one or a combination of two or more of water, acetonitrile, ethanol, propanol, isopropanol, and butanol.

[0027] According to a specific embodiment of the present invention, preferably, the ligand includes one or more of sorbic acid, salicylic acid, nicotinamide, and lactic acid, more preferably sorbic acid.

[0028] According to a specific embodiment of the present invention, preferably, the protective agent comprises one or a combination of two or more of the following: bis(hexadecyl)dimethylammonium halide, bis(tetradecyl)dimethylammonium halide, bis(dodecyl)dimethylammonium halide, bis(decyl)dimethylammonium halide, hexadecyltrimethylammonium halide, tetradecyltrimethylammonium halide, dodecyltrimethylammonium halide, and decadecyltrimethylammonium halide; wherein the halogen element comprises any one of bromine, iodine, and chlorine; more preferably, the protective agent comprises one or a combination of two or more of the following: bis(hexadecyl)dimethylammonium bromide, bis(tetradecyl)dimethylammonium bromide, bis(dodecyl)dimethylammonium bromide, bis(hexadecyl)dimethylammonium chloride, bis(tetradecyl)dimethylammonium chloride, and dodecyl)dimethylammonium chloride.

[0029] In this invention, the protective agent does not undergo complete hydrolysis; only a portion of the protective agent generates individual positive and negative ions, while the remaining protective agents maintain a tightly bound state of positive and negative ions. The bound positive and negative ion pairs are further concentrated by rotary evaporation to form a multilayered ligand shell morphology to protect the metal core. This multilayered ligand shell can serve as a second ligand. By studying the controllable loading and stacking of the second ligand (protective agent) on the metal surface, the stability of the metal cluster is improved. At the same time, the presence of the multilayered ligand shell improves the dispersion of the metal component, giving the isomeric catalyst with this metal cluster as the active phase excellent catalytic performance.

[0030] According to a specific embodiment of the present invention, preferably, the reducing agent includes one or a combination of two or more of hydrazine hydrate, sodium borohydride, ascorbic acid, and potassium borohydride.

[0031] According to a specific embodiment of the present invention, preferably, the metal compound comprises one or more salts of platinum, palladium, and nickel. More preferably, the metal compound comprises one or more salts of chloroplatinic acid, tetraammineplatinum nitrate, platinum nitrate, palladium nitrate, palladium chloride, nickel chloride, and nickel nitrate; more preferably, it is chloroplatinic acid.

[0032] In some specific embodiments, preferably, the alcohol includes one or more of ethanol, propanol, isopropanol, and glycerol, more preferably ethanol.

[0033] In some specific embodiments, preferably, the mass ratio of water to alcohol is (20-1):1, more preferably (20-5):1, and even more preferably 10:1.

[0034] In this invention, the metal clusters serving as the active phases of the first and second isomeric catalysts are atomically precise clusters with multiple layers of ligand shells protecting their surfaces. The ligand shells have two or more layers and a diameter of 5 nm or more, giving the metal clusters ultra-high stability. The diameter refers to the overall diameter of the multiple ligand shells. The atomically precise clusters refer to macromolecules with precise molecular weight and arrangement, completely uniform size, and possessing a metal core and surface ligands (i.e., the second ligand: multiple ligand shells).

[0035] According to a specific embodiment of the present invention, preferably, the amount of metal clusters added is 0.1wt%-0.6wt% based on the mass of the carrier particles (100%); more preferably, it is 0.2wt%-0.4wt%; the mass of the metal clusters is based on the mass of metal atoms.

[0036] In some specific embodiments, preferably, the carrier particles include molecular sieve, alumina, titanium dioxide, acid solution, binder, and deionized water, with the mass ratio of each component being molecular sieve: alumina: titanium dioxide: acid solution: binder: deionized water = 1:(0.3-9):(0.01-0.5):(0.01-0.6):(0.3-1):(0.2-1).

[0037] In some specific embodiments, preferably, the carrier particles are obtained by uniformly mixing molecular sieves, alumina, titanium dioxide, acid solution, binder, and deionized water, followed by extrusion molding, drying, and calcination.

[0038] In some specific embodiments, preferably, the adhesive is field stem powder and / or methylcellulose.

[0039] In some specific implementations, the alumina may be common alumina such as boehmite.

[0040] In some specific embodiments, preferably, the acid solution is a nitric acid solution and / or a phosphoric acid solution, and the concentration of the acid solution is 5wt%-15wt%.

[0041] In some specific embodiments, preferably, the molecular sieve includes one or a combination of two or more of ZSM-48 molecular sieve, ZSM-12 molecular sieve, and ZSM-22 molecular sieve.

[0042] In some specific embodiments, preferably, the silicon-to-aluminum ratio of the molecular sieve is SiO2 / Al2O3 = 50-200, and more preferably SiO2 / Al2O3 = 100-150.

[0043] In some specific embodiments, preferably, the axial diameter ratio of the molecular sieve is less than 20.

[0044] In some specific embodiments, preferably, the molecular sieve can be a commercially available molecular sieve that meets the requirements for silica-to-alumina ratio and axial-to-diameter ratio, or it can be prepared by the following steps:

[0045] Aluminum source, silicon source, alkali source, crystallization inducer, template agent, deionized water, pore-forming agent, and charge balancing agent are mixed evenly and crystallized at 140-170℃ for 10-48 hours. The mixture is then washed, dried, and calcined. The resulting product is mixed with ammonium chloride at 70-80℃ for 4-6 hours. After washing, drying, and calcination, molecular sieves are obtained.

[0046] According to a specific embodiment of the present invention, preferably, the loading volume ratio of the first isomeric catalyst and the second isomeric catalyst is 1:(1-2). The first isomeric catalyst and the second isomeric catalyst are only distinguished by name, and can be the same catalyst or different catalysts, for example, the silicon-to-aluminum ratio of the molecular sieve in the catalyst support particles is different, or the amount of metal clusters added is different.

[0047] In some specific embodiments, preferably, both the first isocatalyst and the second isocatalyst can be prepared by the following steps:

[0048] The support particles are immersed in a solution containing a metal cluster with multiple ligand shells, ultrasonically vibrated at 30-60°C for 2-6 hours (preferably ultrasonically vibrated at 50°C for 4 hours), dried at 100-120°C for 2-4 hours (preferably dried at 120°C for 2 hours), and calcined in air at 450-600°C for 4-6 hours (preferably calcined at 500-550°C for 6 hours) to obtain the corresponding isomeric catalyst.

[0049] According to a specific embodiment of the present invention, preferably, the reaction conditions when in contact with the first isomer catalyst include: a volume hourly space velocity of 0.2-1.0 h⁻¹. -1 (Preferred to be 0.6-0.8h) -1 The hydrogen-to-oil ratio is 300:1 to 1000:1 (preferably 550:1 to 700:1), and the reaction temperature is 300-400℃ (preferably 320-350℃).

[0050] According to a specific embodiment of the present invention, preferably, the reaction conditions when in contact with the second isomer catalyst include: a volume hourly space velocity of 1.0-2.0 h⁻¹. -1 (Preferred time: 1.5-1.6h) -1 The hydrogen-to-oil ratio is 300:1 to 1000:1 (preferably 550:1 to 800:1), and the reaction temperature is 300-400℃ (preferably 330-350℃).

[0051] In some specific embodiments, preferably, in step (1), the conditions for hydrorefining are: temperature 210-300℃, pressure 2.0-4.0 MPa, and volume hourly space velocity 1.0-2.5 h⁻¹. -1 Hydrogen-to-oil ratio (50-100):1.

[0052] In some specific embodiments, preferably, in step (3), the conditions for the purification reaction are: temperature 210-300℃, pressure 2.0-4.0MPa, and volume hourly space velocity 1.0-2.5h. -1 Hydrogen-to-oil ratio (50-100):1.

[0053] In some specific embodiments, preferably, the feedstock oil is Fischer-Tropsch wax and / or hydrocracking tail oil, more preferably hydrocracking tail oil. The Fischer-Tropsch wax originates from coal chemical industry, and the hydrocracking tail oil originates from petrochemical industry.

[0054] The present invention also provides a lubricating oil base oil, which is prepared by the above-described production method.

[0055] According to a specific embodiment of the present invention, preferably, the viscosity index of the lubricating oil base oil is above 111, the pour point is below -10°C (preferably below -15°C), and the cloud point is below -6°C (preferably below -7°C). Wherein, a pour point below -10°C means a pour point of -10°C or lower; a cloud point below -6°C means a cloud point of -6°C or lower.

[0056] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0057] (1) The method for producing lubricating oil base oil provided by the present invention uses metal clusters containing multi-layered ligand shells as the active phase, combined with the pore size of a support containing molecular sieves and suitable acidity, to prepare an isomer catalyst. When used in the production of lubricating oil base oil, it is beneficial to the isomerization reaction of long-chain alkanes, producing more bi-branched or multi-branched isomers. Among them, the small crystallite and small axis-to-diameter ratio of the molecular sieve in the support are conducive to the rapid diffusion of bi-branched or multi-branched isomer products from the pores, thereby reducing the occurrence of cracking reaction; as for the active phase, by adding a protective agent and a reducing agent to the metal precursor solution and performing multiple slow distillations, a metal cluster solution containing multi-layered ligand shells can be obtained. The dynamic loading of the multi-layered ligand shells on the metal surface can prevent excessive metal aggregation, thereby controlling the metal dispersion.

[0058] (2) The method for producing lubricating oil base oil provided by the present invention enables the middle fraction and bottom wax to flow through an isomer catalyst for reaction, and the reaction conditions can be flexibly adjusted according to different raw materials and target products, thereby controlling the reaction depth.

[0059] (3) The lubricating oil base oil provided by the present invention has the characteristics of high yield, low cloud point, low pour point and high viscosity index. Attached Figure Description

[0060] Figure 1 This is a production flow diagram of the lubricating oil base oil in Embodiment 1 of the present invention.

[0061] Figure 2 The curve showing the actual yield of the lubricating oil base oil in Example 1 as a function of time.

[0062] Figure 3The results are MALDI-Tof MS mass spectrometry of isomer catalyst A2 after a period of time in the isomerization reaction.

[0063] Figure 4 This is a dark-field scanning transmission electron microscope image of the isomeric catalyst A2 in Example 2.

[0064] Figure 5 Dark-field scanning transmission electron microscopy image of the isomeric catalyst A2 parallel to the main pore direction.

[0065] Figure 6 Dark-field scanning transmission electron microscopy image of the isomeric catalyst A2 in the direction perpendicular to the main pores.

[0066] Figure 7 Dark-field scanning transmission electron microscopy image of the ZSM-22 molecular sieve prepared in Example 1. Detailed Implementation

[0067] 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.

[0068] Example 1:

[0069] This embodiment provides a method for producing a lubricating oil base oil, specifically including the following steps:

[0070] 1. Preparation of ZSM-22 molecular sieve: 0.12g sodium aluminate, 18g silica, 0.48g NaOH, 1.06g sodium sulfate, 0.05g hexamethylammonium chloride, 5.4g 1,8-octanediamine, 81g deionized water, 4.7g polyhexamethylene biguanide, and 30g ethylene glycol were mixed evenly and crystallized at 170℃ for 10 hours. The mixture was then washed, dried, and calcined at 480℃ for 12 hours. The resulting product was mixed with ammonium chloride at 80℃ for 6 hours, washed, dried, and calcined at 500℃ for 12 hours to obtain ZSM-22 molecular sieve, denoted as molecular sieve Z2. The dark-field scanning transmission electron microscope image of molecular sieve Z2 is shown below. Figure 7 As shown, its silicon-to-aluminum ratio (SiO2 / Al2O3) is 100, and its shaft-to-diameter ratio is 16.

[0071] 2. Preparation of carrier particles: 10g Z2 molecular sieve, 90g pseudoboehmite, 5g titanium dioxide, 6g phosphoric acid solution (concentration of 15wt%), 10g methylcellulose and 10g deionized water are mixed evenly, extruded, dried and calcined at 200℃ for 20 hours.

[0072] 3. Preparation of metal cluster solution: Dissolve 0.63g of chloroplatinic acid in a mixed solution containing 54.56g of deionized water, 5.45g of ethanol, and 2.07g of sorbic acid, and mix at 50°C for 2 hours to prepare a metal precursor solution; then add 5mL of isopropanol, 290mg of sodium borohydride, and 28g of cetyltrimethylammonium bromide and mix, then concentrate to 30% using a rotary evaporator, add isopropanol to the original volume, and stir at 250rpm for 10 hours. Repeat this step 4 times to obtain metal clusters containing multiple layers of ligand shells; the number of ligand shell layers is 2, and the diameter of the ligand shell is 6nm.

[0073] 4. Preparation of heterogeneous catalyst: The support particles are immersed in a solution containing a metal cluster with multiple ligand shells, ultrasonically vibrated at 40°C for 4 hours, dried at 120°C for 2 hours, and calcined at 500°C in air for 4 hours to obtain the heterogeneous catalyst, denoted as heterogeneous catalyst A1.

[0074] 5. Preparation of lubricating oil base oil: such as Figure 1 As shown, hydrocracking tail oil was used as feedstock and then hydrorefined (the hydrorefining reaction conditions were mild: temperature 260℃, pressure 3.0 MPa, and volumetric hourly space velocity 2.0 h⁻¹). -1 The hydrogen-to-oil ratio (75:1) is fed into a fractionating column for cutting, yielding light components (170-300℃), middle fractions (300-500℃), and bottom wax (>500℃). The middle fraction undergoes isomerization in isomerization reactor one, which is packed with a first isomerization catalyst. The bottom wax undergoes isomerization in isomerization reactor two, which is packed with a second isomerization catalyst. Both the first and second isomerization catalysts are isomerization catalyst A1. The reaction products from isomerization reactors one and two are mixed and refined together in a refining column (refining reaction conditions are mild: temperature 260℃, pressure 3.0 MPa, volumetric hourly space velocity 2.0 h⁻¹). -1 The hydrogen-to-oil ratio is 75:1. Then, it enters a fractionation tower for fractionation and cutting, and the fraction above 480℃ is taken to obtain high-quality heavy lubricating oil base oil fraction.

[0075] The loading volume ratio of the first isomer catalyst to the second isomer catalyst is 1:2; the reaction conditions for isomer reactor one are: volume hourly space velocity (VHSV) of 0.8 h⁻¹. -1 The hydrogen-to-oil ratio was 600:1, and the reaction temperature was 330℃; the reaction conditions for the second isomer reactor were: volume hourly space velocity (VHSV) of 1.5 h⁻¹. -1 The hydrogen-to-oil ratio was 800:1, and the reaction temperature was 330℃.

[0076] The yield of the lubricating oil base oil produced in this embodiment is shown in Table 1. Here, HK refers to the vapor phase temperature when the first drop of liquid is distilled out; the cut yield is the weight percentage of each fraction after the liquid product is cut; the actual yield = process liquid yield × cut yield.

[0077] Table 1. Yield of lubricating oil base oil produced in Example 1

[0078] Temperature range of the distillate / °C HK-43 43-160 160-280 280-400 400-445 445-480 ＞480 Cutting yield 5.62％ 0.75％ 1.91％ 10.85％ 6.66％ 11.91％ 57.88％ Actual yield 4.74％ 0.63％ 1.61％ 9.14％ 5.61％ 10.04％ 48.77％

[0079] As shown in Table 1, the actual yield of the lubricating oil base oil (>480℃ fraction) produced in Example 1 was 48.77%. Tests revealed that the heavy lubricating oil base oil (>480℃ fraction) had a viscosity index (standard GB / T 265) of 111, a pour point (standard GB / T3535-2006) of -18.1℃, and a cloud point (standard GB / T6986-2014) of -12.2℃. It exhibits a high viscosity index and low pour and cloud points. These product indicators demonstrate the effectiveness of using metal clusters containing multi-layered ligand shells as the active phase of a catalyst in the production of lubricating oil base oils. Specifically, the protection provided by the multi-layered ligand shells allows the metal clusters to remain on the catalyst surface, thereby promoting catalytic effects with the same metal loading and demonstrating high practicality.

[0080] In this embodiment, the actual yield of heavy lubricating oil base oil changes over time during continuous production as follows: Figure 2 As shown, from Figure 2 As can be seen from this, Pt is protected by a multi-layered ligand spherical shell. 32 (CTA + ·Br - ) 20 Atom-precise clusters, as isomeric catalysts of the active phase, can continuously produce high-quality heavy lubricating oil base oils in production processes exceeding 1000 hours, with an actual yield maintained above 48%.

[0081] Example 2:

[0082] This embodiment provides a method for producing a lubricating oil base oil, specifically including the following steps:

[0083] 1. Preparation of ZSM-48 molecular sieve: 3.22g aluminum sulfate, 36g silica sol (40wt% solid content), 0.06g NaOH, 0.06g NaCl, 4.7g hexamethyldiammonium bromide, 1.4g cyclohexylamine, 24g deionized water, 0.74g Triton X-100, and 24g glycerol were mixed evenly and crystallized at 140℃ for 48 hours. The mixture was then washed, dried, and calcined at 500℃ for 12 hours. The resulting product was mixed with ammonium chloride at 70℃ for 4 hours, washed, dried, and calcined at 550℃ for 12 hours to obtain ZSM-48 molecular sieve, denoted as molecular sieve Z1. Molecular sieve Z1 has a silicon-to-aluminum ratio (SiO2 / Al2O3) of 50 and an axis-to-diameter ratio of 19.

[0084] 2. Preparation of carrier particles: 100g Z1 molecular sieve, 30g pseudoboehmite, 1g titanium dioxide, 1g nitric acid solution (concentration of 5wt%), 30g field stem powder and 20g deionized water are mixed evenly, extruded into strips, dried and calcined at 200℃ for 18 hours to obtain carrier particles.

[0085] 3. Preparation of metal cluster solution: Dissolve 0.21g of chloroplatinic acid in a mixed solution containing 57.14g of deionized water, 2.86g of ethanol, and 1.03g of sorbic acid, and mix at 50℃ for 2 hours to prepare a metal precursor solution; then add 5mL of acetonitrile, 97mg of sodium borohydride, and 9.38g of dihexyldimethylammonium bromide and mix, then concentrate to 20% using a rotary evaporator, add acetonitrile to the original volume, and stir at 200rpm for 8 hours. Repeat this step 3 times to obtain metal clusters containing multiple layers of ligand shells; the number of ligand shell layers is 2, and the diameter of the ligand shell is 5nm.

[0086] 4. Preparation of heterogeneous catalyst: The support particles are immersed in a solution containing metal clusters protected by multiple layers of ligand spherical shells, ultrasonically vibrated at 30°C for 2 hours, dried at 120°C for 2 hours, and calcined at 500°C in air for 4 hours to obtain the heterogeneous catalyst, denoted as heterogeneous catalyst A2.

[0087] 5. Preparation of lubricating oil base oil: Using hydrocracking tail oil as feedstock, after hydrorefining (the hydrorefining reaction conditions are mild: temperature 210℃, pressure 2.0MPa, volume hourly space velocity 1.5h⁻¹). -1The hydrogen-to-oil ratio (50:1) is fed into a fractionating column for cutting, yielding light components (170-300℃), middle fractions (300-500℃), and bottom wax (>500℃). The middle fraction undergoes isomerization in isomerization reactor one, which is packed with a first isomerization catalyst. The bottom wax undergoes isomerization in isomerization reactor two, which is packed with a second isomerization catalyst. Both the first and second isomerization catalysts are isomerization catalyst A2. The reaction products from isomerization reactors one and two are mixed and refined together in a refining column (refining conditions: temperature 210℃, pressure 2.0 MPa, volume hourly space velocity 1.5 h⁻¹). -1 The hydrogen-to-oil ratio is 50:1. Then, it enters the fractionation tower for fractionation and cutting, and the fraction above 490℃ is taken to obtain high-quality heavy lubricating oil base oil fraction.

[0088] The loading volume ratio of the first isomer catalyst to the second isomer catalyst is 1:1; the reaction conditions for isomer reactor one are: volume hourly space velocity (VHSV) of 0.75 h⁻¹. -1 The hydrogen-to-oil ratio was 550:1, and the reaction temperature was 350℃; the reaction conditions for the second isomer reactor were: volume hourly space velocity (VHSV) of 1.6 h⁻¹. -1 The hydrogen-to-oil ratio is 700:1, and the reaction temperature is 340℃.

[0089] The yield of the lubricating oil base oil produced in this embodiment is shown in Table 2. Here, HK refers to the vapor phase temperature when the first drop of liquid is distilled out; the cut yield is the weight percentage of each fraction after the liquid product is cut; the actual yield = process liquid yield × cut yield.

[0090] Table 2. Yield of lubricating oil base oil produced in Example 2

[0091] Temperature range of the distillate / °C HK-44 44-160 160-280 280-400 400-445 445-490 ＞490 Cutting yield 7.00％ 0.74％ 2.07％ 10.56％ 6.53％ 21.70％ 46.79％ Actual yield 6.14％ 0.65％ 1.81％ 9.26％ 5.72％ 19.02％ 41.02％

[0092] As shown in Table 2, the actual yield of the lubricating oil base oil (>490℃ fraction) produced in Example 2 was 41.02%. Testing revealed that the heavy lubricating oil base oil (>490℃ fraction) had a viscosity index (standard GB / T 265) of 120, a pour point (standard GB / T3535-2006) of -15℃, and a cloud point (standard GB / T6986-2014) of -7.3℃. It exhibits a high viscosity index and low pour and cloud points. These product indicators demonstrate the effectiveness of using metal clusters containing multi-layered ligand shells as the active phase of a catalyst in the production of lubricating oil base oils. Specifically, the protection provided by the multi-layered ligand shells allows the metal clusters to remain on the catalyst surface, thereby promoting catalytic effects with the same metal loading and demonstrating high practicality.

[0093] In this embodiment, the results of MALDI-Tof MS mass spectrometry analysis of the isomeric catalyst A2 after a period of time used in base oil production are as follows: Figure 3 As shown; the metal clusters containing multilayered ligand shells on the isomeric catalyst A2 are Pt 32 (CTA + ·Br - ) 20 Atom-precise clusters, comprising 32 Pt atomic cores and 20 CTA atoms. + Cation (hexadecyltrimethylammonium cation) and 20 Br - The bound ion pairs formed by anions (CTA) + ·Br - ), and was multi-layered (CTA) + ·Br - ) Ligand shell protection; from Figure 3 As can be seen from the data, the main peak is 13531 Da, indicating that all the peaks were (CTA) + ·Br - Pt with multilayered ligand spherical shell protection 32 (CTA + ·Br - ) 20 The atomically precise clusters all have the same molecular weight, and the side peak at 13167 Da on the left differs from the main peak by one CTA. + ·Br - The mass of the bound positive and negative ion pairs; furthermore, a cluster of satellite peaks near the main peak at 13531 Da indicates that Pt 32 (CTA + ·Br - ) 20 Atomic precision clusters carry from (CTA) + ·Br - ) Br - Halogen ions.

[0094] The dark-field scanning transmission electron microscopy (HAADF-STEM) image of the isomeric catalyst A2 prepared in this embodiment is shown below. Figure 4 As shown, from Figure 4 As can be seen, the support for the isomeric catalyst A2 is indeed loaded with (CTA) + ·Br - Pt with multilayered ligand spherical shell protection 32 (CTA + ·Br - ) 20 Atomic precision clusters.

[0095] The dark-field scanning transmission electron microscopy (HAADF-STEM) image of the isomeric catalyst A2 prepared in this embodiment is shown below. Figure 5 and Figure 6 The above, wherein, Figure 5 This is a HAADF-STEM image parallel to the main channel. Figure 6 This is a HAADF-STEM image perpendicular to the main channel. From Figure 5 , Figure 6 As can be seen, the molecular sieve channels of the isomeric catalyst A2 do not contain (CTA) + ·Br - Pt with multilayered ligand spherical shell protection 32 (CTA + ·Br - ) 20 The atomically precise clusters indicate that the presence of multilayered ligand shells can hinder Pt. 32 (CTA + ·Br - ) 20 Precise clusters of atoms enter the pores, thereby allowing Pt to... 32 (CTA + ·Br - ) 20 The atomically precise clusters remain only on the surface of the heterogeneous catalyst A2, which improves the utilization rate of the active metal.

[0096] Comparative Example 1:

[0097] This comparative example provides a method for producing a lubricating oil base oil, specifically including the following steps:

[0098] 1. Preparation of carrier particles: Weigh 100g ZSM-48 molecular sieve, 20g boehmite, 60g acid solution (obtained by diluting 9.23g 65wt% nitric acid with 50.77g deionized water), 4.54g field stem powder, 0.46g titanium dioxide, and 49.23g deionized water, mix them evenly, knead and extrude them into strips to form catalyst carrier particles.

[0099] 2. Preparation of metal precursor solution: Dissolve 0.21g of chloroplatinic acid in a mixed solution containing 57.14g of deionized water and 2.86g of ethanol, and mix at 50℃ for 2 hours to prepare a metal precursor solution.

[0100] 3. Preparation of heterogeneous catalyst: The support particles are immersed in a metal precursor solution, ultrasonically vibrated at 30°C for 2 hours, dried at 120°C for 2 hours, and calcined at 500°C in air for 4 hours to obtain the heterogeneous catalyst, denoted as heterogeneous catalyst A3.

[0101] 4. Preparation of Lubricating Oil Base Oil: Using hydrocracking tail oil as feedstock, the oil is fractionated in a fractionation tower to obtain light components (170-300℃), middle fractions (300-500℃), and bottom wax (>500℃). The middle fraction is fed into isomerization reactor one for isomerization, which is packed with a first isomerization catalyst. The bottom wax is fed into isomerization reactor two for isomerization, which is packed with a second isomerization catalyst. Both the first and second isomerization catalysts are isomerization catalyst A3. The reaction products from isomerization reactor one and isomerization reactor two are mixed and refined together in a refining tower. Then, the mixture is fractionated in a fractionation tower to obtain the fraction with a temperature above 490℃, which is a high-quality heavy lubricating oil base oil fraction.

[0102] The loading volume ratio of the first isomer catalyst to the second isomer catalyst is 1:1; the reaction conditions for isomer reactor one are: volume hourly space velocity (VHSV) of 0.2 h⁻¹. -1 The hydrogen-to-oil ratio was 300:1, and the reaction temperature was 340℃; the reaction conditions for the second isomer reactor were: volume hourly space velocity (VHSV) of 2.0 h⁻¹. -1 The hydrogen-to-oil ratio is 1000:1, and the reaction temperature is 330℃.

[0103] The yields of the lubricating base oil produced in this comparative example are shown in Table 3. Here, HK refers to the vapor phase temperature when the first drop of liquid is distilled out; the cut yield is the weight percentage of each fraction after the liquid product has been cut; and the actual yield = process liquid yield × cut yield.

[0104] Table 3. Yield of lubricating base oil produced in Comparative Example 1

[0105] Temperature range of the distillate / °C HK-42 42-160 160-280 280-400 400-445 445-490 ＞490 Cutting yield 9.82％ 1.69％ 4.19％ 25.17％ 20.30％ 13.48％ 25.36％ Actual yield 8.25％ 1.42％ 3.52％ 21.14％ 17.05％ 11.32％ 21.30％

[0106] As shown in Table 3, the actual yield of the lubricating oil base oil (>490℃ fraction) produced in Comparative Example 1 was 21.30%, lower than that of the Example. Testing revealed that the viscosity index (standard GB / T265) of the heavy lubricating oil base oil (>490℃ fraction) was 102, the pour point (standard GB / T3535-2006) was -8.3℃, and the cloud point (standard GB / T6986-2014) was -5.2℃. Its viscosity index was lower than that of the Example, while its pour point and cloud point were higher. Therefore, without using metal clusters containing multilayered ligand shells as the active phase of the catalyst, the yield and performance of the heavy lubricating oil base oil were unsatisfactory.

Claims

1. A method for producing a lubricating oil base oil, wherein, The production method includes: (1) Hydrorefining the feedstock oil and then fractionating it to obtain light components, middle fractions and bottom wax; (2) The middle fraction is brought into contact with the first isomeric catalyst and reacted, and the bottom wax is brought into contact with the second isomeric catalyst and reacted; (3) After mixing the reaction products of the middle fraction and the bottom wax of the tower, a refining reaction is carried out, and then the mixture is fractionated to obtain the lubricating oil base oil. The first and second isomeric catalysts both include support particles and metal clusters containing multilayered ligand shells, with the metal clusters loaded on the support particles. The distillation range of the light component is 170-300℃, the distillation range of the middle fraction is 300-500℃, and the distillation range of the bottom wax is >500℃. In step (3), the base oil of the lubricating oil has a distillation range of >480℃.

2. The production method according to claim 1, wherein, The method for preparing the metal cluster containing multilayered ligand shells includes: (a) Dissolve a metal compound in a mixture containing water, alcohol and ligand, and mix to obtain a metal precursor solution; (b) Add solvent, protective agent and reducing agent to metal precursor solution and mix. After concentration and stirring, add solvent. Repeat the concentration, stirring and solvent addition operations to obtain metal clusters containing multilayer ligand shells. The molar ratio of the metal compound to the protective agent is 1:10 to 1:100; And / or, the molar ratio of the ligand to the metal compound is (6-18):1, and the molar ratio of the metal compound is based on the metal element. And / or, in terms of the number of electrons, the ratio of the number of electrons lost by the metal to the number of electrons gained by the reducing agent in the metal compound is 1:1 to 1:

10.

3. The production method according to claim 2, wherein, The ligands include one or more of sorbic acid, salicylic acid, nicotinamide, and lactic acid.

4. The production method according to claim 2, wherein, The protective agent includes one or more of the following: dihexadecyl dimethyl ammonium halide, ditetradecyl dimethyl ammonium halide, didodecyl dimethyl ammonium halide, didecyl dimethyl ammonium halide, hexadecyl trimethyl ammonium halide, tetradecyl trimethyl ammonium halide, dodecyl trimethyl ammonium halide, and decadecyl trimethyl ammonium halide. Halogens include any one of bromine, iodine, and chlorine.

5. The production method according to claim 2, wherein, The reducing agent includes one or a combination of two or more of hydrazine hydrate, sodium borohydride, ascorbic acid, and potassium borohydride.

6. The production method according to claim 2, wherein, The metal compound includes one or more salts of platinum, palladium, and nickel.

7. The production method according to claim 6, wherein, The metal compound includes one or more of the following: chloroplatinic acid, tetraammineplatinum nitrate, platinum nitrate, palladium nitrate, palladium chloride, nickel chloride, and nickel nitrate.

8. The production method according to claim 1, wherein, The amount of metal clusters added is 0.1wt%-0.6wt%, with the mass of the carrier particles being 100%. The mass of the metal clusters is based on the mass of metal atoms.

9. The production method according to claim 1, wherein, The loading volume ratio of the first isocatalyst and the second isocatalyst is 1:(1-2).

10. The production method according to claim 1, wherein, The reaction conditions when in contact with the first isomer catalyst include a volume hourly space velocity of 0.2–1.0 h⁻¹. -1 The hydrogen-to-oil ratio is 300:1 to 1000:1, and the reaction temperature is 300-400℃; And / or, the reaction conditions when in contact with the second isomer catalyst include: a volume hourly space velocity of 1.0-2.0 h⁻¹. -1 The hydrogen-to-oil ratio is 300:1 to 1000:1, and the reaction temperature is 300-400℃.

11. A lubricating oil base oil, which is prepared by the production method according to any one of claims 1-10.

12. The lubricating oil base oil according to claim 11, wherein, The viscosity index of the base oil for the lubricating oil is above 111, the pour point is below -10℃, and the cloud point is below -6℃.

Images