Base oil composition, internal combustion engine oil and preparation and application of internal combustion engine oil

Abstract

The invention provides a base oil composition, internal combustion engine oil and preparation and application of the internal combustion engine oil. The base oil composition comprises an API-IV base oil and an alkylated naphthalene oligomer, and the alkylated naphthalene oligomer is prepared by taking naphthalene as a raw material, carrying out an oligomerization reaction to obtain naphthalene oligomer, and then carrying out an alkylation reaction with linear alpha-olefin to obtain the alkylated naphthalene oligomer. Due to the special molecular structure characteristic of the alkylated naphthalene oligomer, the alkylated naphthalene oligomer has higher viscosity index, thermal stability and thermal oxidation stability and lower pour point and evaporation loss, and meanwhile, the alkylated naphthalene oligomer is beneficial to reducing abrasion. In addition, the alkylated naphthalene oligomer can improve the compatibility of the non-polar poly-alpha-olefin base oil and the polar additive, so that various additives can better play the role, the alkylated naphthalene oligomer is used for internal combustion engine oil, the quality of sediment such as oil sludge can be reduced, ester bonds do not exist in molecules of the alkylated naphthalene oligomer, and the viscosity of the alkylated naphthalene oligomer is reduced. The acid value increase caused by hydrolysis at high temperature is avoided.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil base oil technology, and relates to base oil compositions containing alkylated naphthalene oligomers and internal combustion engine oils, as well as their preparation and uses. Background Technology

[0002] Long-chain alkylnaphthalenes possess high viscosity index, low volatility, good thermal stability, oxidative stability, and hydrolytic activity, making them suitable for use as lubricants, lubricant additives, and functional fluids. The lubricating performance of alkylnaphthalenes as a base oil is generally related to the number and length of the alkyl chains on the naphthalene ring. Because highly selective polyalkylated naphthalene products are difficult to obtain through the Friedel-Crafts reaction of naphthalene with terminal olefins alone, progress in the molecular design of alkylnaphthalene compounds has been limited.

[0003] An internal combustion engine is a widely used power machine that converts the heat energy released from the combustion of fuel inside the machine into power. Common internal combustion engines include diesel engines and gasoline engines, which are widely used in various vehicles, ships, and construction machinery. Because internal combustion engines operate under high temperatures, high speeds, heavy loads, and large temperature differences, their working environment is extremely complex. They must adapt to highway driving, the fluctuating speeds in urban areas, and even operation in swamps or frigid deserts. All of these factors necessitate the use of engine oil to reduce friction, cool the engine, seal it, and dampen vibrations, thus ensuring the engine's long lifespan and efficient operation.

[0004] Modern internal combustion engine manufacturing is trending towards lighter weight, higher density, higher precision, and lower clearances. In precision internal combustion engines, the clearances between piston rings and cylinder liners, and between piston rings and ring grooves, are even lower. High-viscosity engine oil is no longer needed to improve sealing; low-viscosity engine oil can fully meet the sealing requirements. Moreover, low-viscosity engine oil has better fluidity at low temperatures, allowing it to be quickly pumped to all friction surfaces during cold starts, reducing wear and engine resistance. At the same time, low-viscosity oil can better dissipate waste heat, ensuring that the engine temperature remains within a suitable range. Therefore, low-viscosity internal combustion engine oil can reduce fuel consumption and exhaust emissions, aligning with the mainstream of energy conservation and environmental protection, and becoming a new trend in automotive technology development.

[0005] Internal combustion engine sliding bearings bear heavy loads. Under high load and extreme pressure conditions, low-viscosity engine oil also requires good anti-friction properties to transform point contact between parts into surface contact of the liquid, disperse stress, reduce vibration, and thus reduce frictional wear between parts. In addition, during operation, internal combustion engines generate various carbonaceous deposits such as varnish and sludge due to lubricant oxidation. Internal combustion engine oil should also have good detergency and dispersancy, keeping oxidation products in suspension and dispersion within the oil. Through circulation, these products can be washed away from the working surface, preventing blockage of oil passages or accumulation as wear media.

[0006] To meet the above requirements of internal combustion engine oils, high-performance fully synthetic lubricants are needed, especially those with polyalphaolefin (PAO) as the main component. PAO is an important base material for lubricants, possessing excellent lubrication properties. However, PAO is composed of a single hydrocarbon compound with very low molecular polarity, resulting in low solubility and dispersibility for polar additives, polar sludge, and other deposits during use. Therefore, PAO base oils require auxiliary oils to improve the solubility of polar additives and the dispersibility of deposits generated during oxidation in internal combustion engines. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides an alkylated naphthalene oligomer, a method for preparing the oligomer, its application, and an internal combustion engine oil using the oligomer. The alkylated naphthalene oligomer exhibits higher oil film thickness, thermal stability, and thermal oxidation stability, reduces evaporation loss, and improves the compatibility between non-polar polyalphaolefin base oils and polar additives, allowing various additives to better perform their functions.

[0008] To achieve the above objectives, the present invention adopts the following technical solution.

[0009] In a first aspect, the present invention provides an alkylated naphthalene oligomer, wherein the preparation of the alkylated naphthalene oligomer includes: using naphthalene as a raw material, undergoing an oligomerization reaction to obtain oligo-naphthalene, and then undergoing an alkylation reaction with a linear α-olefin to obtain the alkylated naphthalene oligomer.

[0010] Among them, chloroaluminate ionic liquid is used to catalyze the oligomerization and alkylation reactions of naphthalene compounds.

[0011] In the oligomerization and alkylation processes, an oxidant is used, preferably selected from copper chloride or ferric chloride.

[0012] The alkylated naphthalene oligomers include, but are not limited to, the following compounds: monosubstituted alkyl dinaphthalene, disubstituted alkyl dinaphthalene, trisubstituted alkyl dinaphthalene, monosubstituted alkyl trimenaphthalene, disubstituted alkyl trimenaphthalene, trisubstituted alkyl trimenaphthalene, monosubstituted alkyl tetranaphthalene, disubstituted alkyl tetranaphthalene, monosubstituted alkyl pentanaphthalene, and disubstituted alkyl pentanaphthalene. Preferably, the alkylated naphthalene oligomers further include: monosubstituted alkyl naphthalene, disubstituted alkyl naphthalene, trisubstituted alkyl naphthalene, monosubstituted alkyl anthracene, disubstituted alkyl anthracene, monosubstituted alkyl phenanthrene, disubstituted alkyl phenanthrene, monosubstituted alkyl 1-phenylnaphthalene, disubstituted alkyl 1-phenylnaphthalene, monosubstituted alkyl 2-phenylnaphthalene, and disubstituted alkyl 2-phenylnaphthalene.

[0013] Secondly, the preparation method of the alkylated naphthalene oligomers mentioned above includes: using naphthalene as a raw material, obtaining oligo-naphthalene through an oligomerization reaction, and then obtaining alkylated naphthalene oligomers through an alkylation reaction with linear α-olefins.

[0014] Among them, chloroaluminate ionic liquid is used to catalyze the oligomerization and alkylation reactions of naphthalene compounds.

[0015] In the oligomerization and alkylation processes, an oxidant is used, preferably selected from copper chloride or ferric chloride.

[0016] The oligomerization reaction is carried out at a temperature of 80-120℃, preferably 100-120℃, and the reaction time is 1-12 hours, preferably 2-6 hours; the alkylation reaction is carried out at a temperature of 60-100℃, preferably 70-90℃, and the reaction time is 2-12 hours, preferably 3-6 hours.

[0017] The preferred chemical formula for the catalyst, aluminochloroaluminate ionic liquid, is: [R3NH] + [Al x Cl 3x+1 ] - R is selected from methyl, ethyl or isopropyl, and x is a non-zero positive integer, preferably x = 2.

[0018] The molar ratio of Al in the raw material naphthalene to the catalyst chloroaluminate ionic liquid ranges from 2:1 to 8:1, and preferably, the molar ratio of Al in the alkylated naphthalene oligomer to the catalyst chloroaluminate ionic liquid ranges from 4:1.

[0019] The molar ratio of raw material naphthalene to oxidant is in the range of 5:1 to 10:1, preferably in the range of 8:1.

[0020] The molar ratio of raw material naphthalene to α-olefin ranges from 2:1 to 10:1, and preferably, the molar ratio of raw material naphthalene to oxidant ranges from 4:1.

[0021] Furthermore, α-olefins are added to oligonaphthalenes in a one-time addition or by gradual dropwise addition to carry out alkylation reactions.

[0022] Thirdly, the present invention provides the application of the alkylated naphthalene oligomers described above in functional fluids such as lubricants and heat transfer fluids.

[0023] Preferably, the functional fluid, such as the lubricant or heat transfer fluid, comes into direct contact with at least one surface of the rubber-based sealing material.

[0024] Preferably, the above-described alkylated naphthalene oligomers are used in immersion coolants.

[0025] Fourthly, the present invention provides a base oil composition comprising the alkylated naphthalene oligomers described above.

[0026] Furthermore, a base oil composition comprises: an API-IV base oil and the alkylated naphthalene oligomer described above. Preferably, the API-IV base oil is a polyalphaolefin.

[0027] Furthermore, the base oil composition comprises:

[0028] API-IV group base oil content: 75-97% by weight;

[0029] The alkylated naphthalene oligomer comprises 3–25% by weight.

[0030] The polyalphaolefin has a kinematic viscosity of 1–10 mm at 100°C. 2 Preferably, the kinematic viscosity of the polyalphaolefin at 100°C is 2–8 mm / s. 2 / s, and more preferably, the kinematic viscosity of the polyalphaolefin at 100°C is 2–6 mm. 2 / s.

[0031] Preferably, the polyalphaolefin is selected from metallocene polyalphaolefin, non-metallocene polyalphaolefin, or a mixture of both, wherein the metallocene polyalphaolefin is prepared by catalyzing the polymerization of alphaolefin using a metallocene catalyst system, and the non-metallocene polyalphaolefin is prepared by catalyzing the polymerization of alphaolefin using a non-metallocene catalyst system.

[0032] Fifthly, the present invention provides an internal combustion engine oil, comprising:

[0033] The base oil composition described above comprises 75-95% by weight;

[0034] The tackifier comprises 1-10% by weight.

[0035] The tackifier is selected from any one or a combination of two of high-viscosity metallocene polyalphaolefins or methacrylate copolymers, wherein the high-viscosity metallocene polyalphaolefin has a kinematic viscosity ≥100 mmHg at 100°C. 2 / s.

[0036] Preferably, the internal combustion engine oil described above further includes: 5-20% by weight of internal combustion engine oil functional additives.

[0037] Among them, functional additives for internal combustion engine oils include at least one of detergents, dispersants, antioxidants, and friction modifiers;

[0038] The detergent is selected from at least one of petroleum sulfonates, synthetic sulfonates, sulfurized alkylphenol salts, naphthenates and alkyl salicylates;

[0039] The dispersant is selected from at least one of succinate, succinimide, ashless phosphonate, boronized polyisobutylene succinimide, and phenolic amine;

[0040] The antioxidant is selected from at least one of 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butyl-4-ethylphenol, 2,4-dimethyl-6-tert-butylphenol, alkylated diphenylamine, N-alkylnaphthylamine, N-phenylnaphthylamine and molybdate;

[0041] The friction modifier is selected from at least one of fatty acids, fatty alcohols, fatty amines and / or their derivatives, and organomolybdenum compounds. Further, the internal combustion engine oil includes: gasoline engine oil, diesel engine oil, and universal gasoline / diesel engine oil, wherein the viscosity grade of the gasoline engine oil, diesel engine oil, and universal gasoline / diesel engine oil is independently selected from at least one of 0W20, 0W30, 0W40, 5W20, 5W30, and 5W40; according to the standards for gasoline, diesel, and railway diesel locomotive engine oils, the gasoline engine oil is API SN or higher, and the diesel engine oil is API CI-4 or higher; the railway diesel locomotive engine oil is selected from multi-grade fourth-generation oils and / or multi-grade fifth-generation oils. Preferably, the gasoline engine oil is API SP.

[0042] In a sixth aspect, the present invention provides a method for preparing the above-described internal combustion engine oil, comprising: taking a base oil composition, a viscosity modifier and an internal combustion engine oil functional additive, mixing them evenly, and stirring until clear and transparent, thereby obtaining the oil.

[0043] In a seventh aspect, the present invention provides an internal combustion engine using the aforementioned internal combustion engine oil.

[0044] The above base oil formulations primarily use low-viscosity polyalphaolefins (PAOs), mixed with higher-viscosity alkylated naphthalene oligomers. The low-viscosity PAOs ensure the base oil's fluidity and low-temperature performance, while the alkylated naphthalene oligomers enhance its anti-friction properties, oxidation stability, and thermal oxidation stability, while reducing evaporation losses. Furthermore, the alkylated naphthalene oligomers improve the compatibility of non-polar PAOs with polar additives, allowing various additives to better perform their functions.

[0045] This invention involves alkylating a naphthalene oligomer with a long-chain terminal olefin to obtain an alkylated naphthalene oligomer with an aromatic core and alkyl side arms. Compared to conventional alkylnaphthalenes, the alkylated oligonaphthalene has a larger proportion of aromatic core, which improves viscosity-temperature characteristics (i.e., increases viscosity index) and exhibits a more pronounced wide temperature range, making it suitable as a base oil for functional fluids such as lubricants and heat transfer fluids.

[0046] The above technical solution has the following beneficial technical effects:

[0047] The alkylated naphthalene oligomers proposed in this invention feature a radially arranged side arm formed after the alkylation of an aromatic core and an α-olefin, exhibiting a branched star-shaped structure. This results in higher viscosity index, thermal stability, and thermal oxidation stability, as well as lower pour point and evaporation loss. Furthermore, the π-π stacking interaction between the aromatic rings leads to a more regular molecular arrangement of the alkylated naphthalene oligomers, enabling the formation of a thicker oil film between friction pairs, thus reducing wear. Additionally, the alkylated naphthalene oligomers show better compatibility with commonly used rubber sealing materials, particularly butyl, styrene-butadiene, and nitrile rubbers, preventing significant swelling of the rubber materials.

[0048] In addition, alkylated naphthalene oligomers can improve the compatibility of nonpolar polyalphaolefin base oils with polar additives, allowing various additives to perform better. When used in internal combustion engine oils, they can reduce the mass of deposits such as sludge. Since there are no ester bonds in the molecules of alkylated naphthalene oligomers, hydrolysis at high temperatures can be avoided, which would lead to an increase in acid value. Attached Figure Description

[0049] Figure 1 The results are GC-MS analysis of the alkylated oligonaphthalene products of Examples 1, 6 and Examples 2, 7.

[0050] Figure 2 The results are FTIR analysis of the alkylated oligonaphthalene products of Example 4 and Comparative Example 2.

[0051] Figure 3 Optical interferograms showing the oil film changes of alkylated oligonaphthalene products at different entrainment rates.

[0052] Figure 4The oil film thickness of alkylated oligonaphthalene products at different entrainment rates.

[0053] Figure 5 Comparison of coking plate test results for gasoline engine oil.

[0054] Figure 6 Comparison of coking plate test results for diesel engine oil. Detailed Implementation

[0055] It should be noted that the following detailed description of specific embodiments is illustrative and intended to provide further explanation of this application, rather than limiting the scope of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. Experimental conditions not specifically stated in the embodiments are generally performed under conventional conditions or as recommended by the selling company; materials, reagents, etc., used in the embodiments are commercially available unless otherwise specified.

[0056] Preparation of ionic liquid catalyst and oxidant: The ionic liquid catalyst [Me3NH] was prepared by mixing Me3NHCl, AlCl3, and n-decane solvent in a molar ratio of 0.5:1:1. + [Al2Cl7] - The preparation method includes: continuously introducing high-purity nitrogen gas into the mixing container for protection, and continuously stirring the resulting mixture for 1 hour under a nitrogen atmosphere to obtain the corresponding ionic liquid catalyst.

[0057] Example 1: Preparation of alkylated oligonaphthalene

[0058] Alkylated oligonaphthalene was prepared in a 1L glass reactor equipped with a stirrer. 3.2 mol of naphthalene and 0.4 mol of copper chloride (CuCl2) were weighed and added to the reactor. After heating to 80°C and holding for 15 minutes to allow the naphthalene to completely dissolve, 0.8 mol (based on Al content) of the ionic liquid catalyst [Me3NH3] was added. + [Al2Cl7] - The temperature was increased to 105℃ and reacted for 5 hours. Then the temperature was lowered to 80℃ and 0.8 mol of 1-octene was added dropwise to the reactor. During the addition, the temperature fluctuation was controlled to be no more than ±5℃. The addition was completed in 1.5 hours. The temperature was then maintained at 85℃ for 4 hours. After that, stirring was stopped and alkali solution was added to quench the reaction. The reaction vessel was cooled to ambient temperature, and the lower ionic liquid was separated. The upper organic layer was washed with pure water until it was neutral. Then it was washed once with n-propanol to remove the ionic liquid and alkali solution remaining in the organic phase. Finally, the organic phase was subjected to vacuum distillation at 100℃ to remove light components and unreacted monomers.

[0059] Example 2

[0060] Same as in Example 1, except that 0.8 mol of 1-octene was replaced with 0.8 mol of 1-decene.

[0061] Example 3

[0062] Same as in Example 1, except that 0.8 mol of 1-octene was replaced with 0.8 mol of 1-tetradecene.

[0063] Example 4

[0064] Same as in Example 1, except that 0.8 mol of 1-octene was replaced with 0.8 mol of 1-hexadecene.

[0065] Example 5

[0066] Same as in Example 1, except that 0.8 mol of 1-octene was replaced with 0.8 mol of 1-octadecene.

[0067] Example 6

[0068] Same as in Example 1, except that the temperature of the naphthalene oligomerization reaction was changed from 105°C to 85°C.

[0069] Example 7

[0070] Same as in Example 2, using the ionic liquid catalyst [Me3NH] + [Al2Cl7] - The dosage was changed to 0.2 mol (based on Al).

[0071] Comparative Example 1

[0072] Similar to Example 1, copper chloride (CuCl2) is not added at the beginning of feeding.

[0073] Comparative Example 2

[0074] Similar to Example 4, copper chloride (CuCl2) is not added at the beginning of feeding.

[0075] Comparative Example 3

[0076] The commercial product, NA-LUBE KR-019, is from King Industries Inc.

[0077] Comparative Example 4

[0078] The commercial product, NA-LUBE KR-023, is from King Industries Inc.

[0079] Test section:

[0080] Kinematic viscosity at 100°C and 40°C (KV@100 and KV@40) was tested according to ASTM D445-17a; viscosity index (VI) was tested according to ASTM D2270; flash point was tested according to ASTM D92-16b; pour point was tested according to ASTM D5949-16.

[0081] Average molecular weight and polydispersity index (PDI) test: gel permeation chromatography (GPC) analysis was performed using an Agilent PL gel column packed with cross-linked styrene / divinylbenzene particles, with tetrahydrofuran as the solvent to dissolve the test sample at a flow rate of 1 mL / min. A standard curve was constructed using polystyrene standards with a narrow molecular weight distribution for the test.

[0082] GC-MS analysis was used to quantitatively and qualitatively analyze the molecular structure of the alkylated oligonaphthalene product, and the molecular weight and molecular formula were determined based on the mass-to-charge ratio (m / z) of the separated components.

[0083] The test results are shown in Table 1.

[0084] Table 1

[0085]

[0086] The experimental results above show that the alkylated naphthalene oligomers synthesized in Examples 1-5 under the conditions of naphthalene oligomerization reaction temperature of 105℃ and naphthalene:AlCl3:CuCl2:α-olefin molar ratio of 8:2:1:2 have polydispersity indices (PDI) between 1.27 and 1.36. Their viscosity, viscosity index, and pour point increase with the increase of the number of carbon atoms in the α-olefin, reflecting the structure-property and composition-property relationships. Furthermore, compared with Examples 6 and 7, Comparative Examples 1 and 2, and commercially available Comparative Examples 3 and 4 under other reaction conditions, the alkylated naphthalene oligomers in Examples 1-5 have higher viscosity indices, all exceeding 125. This indicates that the product obtained under these conditions through the polyalkylation of oligonaphthalene with linear 1-olefins exhibits better viscosity-temperature properties, better resistance to temperature changes, and can maintain relatively stable flow properties at different temperatures. Therefore, as a lubricant base oil or heat transfer fluid, it can better fulfill its corresponding role at different temperatures. Meanwhile, as the number of carbon atoms in α-olefins increases, the flash point of the corresponding alkylated oligonaphthalenes increases. This is because the increased number of carbon atoms leads to an increase in the molecular weight and kinematic viscosity of the product, while the decreased volatility results in an increased flash point.

[0087] Table 2 presents the possible chemical structures of the products from the alkylation reaction of oligonaphthalene with α-olefins. Because oligonaphthalene contains numerous alkylating active sites, the alkylated products undergo rearrangement via cationic intermediates to form thermodynamically stable products. Therefore, the same structure may also include different R side chains; that is, the alkylated products are composed of isomers with different side chain structures, resulting in a complex composition. Figure 1 Tables a, b, c, and d present the analytical results of the alkylated oligonaphthalene products of Examples 1 and 6, and Examples 2 and 7. Qualitative analysis of the molecular structure of the products was performed by GC-MS. Based on different retention times, the alkylated oligonaphthalene products were divided into component I, component II, and component III. The main components of each component were determined by detecting their corresponding mass-to-charge ratios, as shown in Table 2.

[0088] Table 2

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099] A comparison of Examples 1 and 6 shows that lowering the temperature of the naphthalene oligomerization reaction results in lower contents of naphthalene oligomers, such as anthracene, phenanthrene, 1-phenylnaphthalene, 2-phenylnaphthalene, dimer naphthalene (1,1-binaphthalene, 1,2-binaphthalene), and trimer naphthalene (1-naphthylbinaphthalene, 2-naphthylbinaphthalene), and higher contents of unreacted naphthalene. This indicates that temperature affects the naphthalene oligomerization reaction; excessively low temperatures are unfavorable for the oligomerization reaction, resulting in more unreacted naphthalene in the reaction system. The addition of α-olefins yields more alkylnaphthalene products. Correspondingly, Example 6 has a relatively lower average molecular weight, kinematic viscosity, and VI. Furthermore, a comparison between Examples 2 and 7 shows that reducing the molar ratio of naphthalene to the ionic liquid catalyst also hinders the naphthalene oligomerization reaction, thus resulting in a higher proportion of low-molecular-weight alkylnaphthalene products in the final alkylated products compared to Example 7.

[0100] The composition of alkylated oligonaphthalene products is very complex. Due to the formation of cationic centers during the alkylation process, a large number of isomers exist, and the boiling points of these isomers are very close, making it very difficult to separate them into single components. At the same time, the base oil used as a lubricant or heat transfer fluid is itself a mixture of multiple components. Therefore, this invention does not further separate these products, and all subsequent tests are conducted in the form of a mixture of multiple components.

[0101] In Comparative Examples 1 and 2, which do not contain the oxidant copper chloride, some naphthalene is reduced to tetrahydronaphthalene during the naphthalene oligomerization process, reducing the number of sites available for alkylation. Therefore, their molecular weight and viscosity index decrease, while their pour point increases. For the commercially available products NA-LUBE KR-019 and NA-LUBE KR-023, their kinematic viscosity is very close to that of Examples 1 and 2, but their viscosity index is lower and their flash point is higher.

[0102] Thermal stability and thermal oxidation stability test

[0103] The thermal stability test was conducted according to the method of ASTM D2070. The test conditions were 200°C for 7 days. Clean copper and iron rods were immersed in 200 mL of the test sample respectively. The change in kinematic viscosity of the sample before and after immersion, the mass of total sludge in the experiment, and the color grade of copper and iron rods after the test were measured.

[0104] The thermal oxidation stability test was conducted according to the rotating oxygen bomb test method of ASTM D2272. 50g of each sample was used for testing. During the test, 0.2wt% of either the phenolic antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl]pentaerythritol ester or the amine antioxidant 4,4-bis(α,α-dimethylbenzyldiphenylamine) was added to the sample. The oxidation stability of the sample was expressed in minutes (min) based on the oxygen bomb test time; a longer oxygen bomb test time indicated higher oxidation stability.

[0105] The results of the thermal stability and thermal oxidation stability tests are shown in Table 3.

[0106] Table 3

[0107]

[0108] As shown in Table 3, the alkylated oligonaphthalenes in Examples 1-7 contain aromatic ring structures of naphthalene and oligonaphthalene. These electron-rich naphthalene rings can capture oxidizing groups generated by the oxidation of hydrocarbon groups in the molecule, making it difficult for the entire oxidation chain to form, thus preventing the oxidation process. At the same time, the oxidation product of oligonaphthalene (naphthol) can also play an antioxidant role. The phenolic hydroxyl group in the naphthol molecule structure easily donates hydrogen atoms, i.e., through proton donation, thereby inhibiting the auto-oxidation chain reaction of free radicals. The thermal stability test reflects the ease with which the test substance undergoes chemical reactions such as oxidation under high temperature conditions. Therefore, it is inferred that the alkylated oligonaphthalenes with complete naphthalene rings have better thermal stability and thermal oxidation stability.

[0109] As shown in Table 3, the thermal stability test revealed that the alkylated oligonaphthalenes of Examples 1-7 exhibited the smallest change in kinematic viscosity and the lowest sludge quality after being subjected to a high temperature of 200℃ for 7 days. They also demonstrated the best oxidative protection against copper and steel, minimizing the oxidation and discoloration of copper and iron rods. Compared to the commercial products of Comparative Examples 3 and 4, they showed advantages, and compared to Comparative Examples 1 and 2, they showed significant advantages. Comparative Examples 1 and 2, lacking the oxidant copper chloride, resulted in the reduction of the naphthalene ring to form a cycloalkane structure. The destruction of the naphthalene ring structure and the inability of the aromatic rings to maintain their continuous correspondence significantly reduced their thermal stability.

[0110] The results of the rotating oxygen bomb test were consistent with the above thermal stability results. The alkylated oligonaphthalenes of Examples 1-7 showed excellent thermal oxidation stability using two different types of antioxidants, which was slightly better than the commercial products of Comparative Examples 3 and 4, and significantly better than Comparative Examples 1 and 2.

[0111] Oil film thickness measurement

[0112] The oil film thickness of the sample was measured using an EHD film measurement system (EHD2, PCS Instruments). This system employs optical interferometry to measure the thickness of the oil film in a rolling steel ball on a disc contact surface. The selected friction pair consisted of a 25.4 mm diameter G5 steel ball and a K9 glass disc coated with a semi-reflective chromium film. The steel ball and glass disc rotated under the drive of a servo motor. Different entrainment speeds could be obtained by controlling the servo motor pulses. Simultaneously, the temperature of the lubricant sample was controlled by a temperature control device. A constant load of 32 N was used, corresponding to a maximum Hertzian pressure of 0.5 GPa in the contact area. The temperature of the lubricant itself was set to 100 °C, and the entrainment speed was set to vary within the range of 100–5000 mm / s. The relative humidity during the experiment was between 40–60%. The change in the central oil film thickness with the entrainment speed was measured when the steel ball / disc combination rolled.

[0113] The oil film thickness test results are shown in the figure. A plot of oil film thickness against entrainment speed yields the test results. As can be seen from the figure, at 100℃, the slopes of the different embodiments and the comparative example are very similar; all show that the oil film thickness increases with increasing entrainment speed. The oil film thickness of Example 2 is significantly higher, which is related to its chemical structure. During the synthesis process, copper chloride, an oxidant, is added to prevent the reduction reaction of the naphthalene ring, thus preserving the complete naphthalene ring and polynaphthalene rings in the molecule. This results in a special spatial arrangement between the naphthalene rings, increasing the oil film thickness through the π-π stacking effect between aromatic rings, leading to higher anti-friction potential. In particular, Example 2 can form a good film thickness even at low entrainment speeds, which is beneficial for reducing wear. When applied to gear oil formulations, a higher film thickness can reduce surface fatigue of gears, help reduce micro-pitting on the gear surface, and ensure gear precision.

[0114] Rubber material compatibility testing: Referring to the method in Appendix D of GB 29743.2, the compatibility of the alkylated oligonaphthalene, comparative sample, and rubber materials in the above embodiments was tested using the long-term storage method. The sealing material to be tested was stored in a container, and the sample was added when the temperature was raised to 80±2℃, ensuring that the fluid sample to be tested completely immersed the sealing material. The container was then closed, and the sealing material was removed after maintaining this temperature for 500 hours. The mass change rate and volume change rate of the sealing material before and after the test were recorded. The sealing material used for compatibility testing was a 25mm×25mm square test piece. The rubber materials selected for testing included nitrile rubber, butyl rubber, styrene-butadiene rubber, chloroprene rubber, and ethylene propylene rubber. The test results are listed in Table 4.

[0115] As shown in Table 4, compared with the commercially available comparative examples 3 and 4, the alkylated oligonaphthalenes of Examples 1 and 2 exhibit better compatibility with nitrile rubber, butyl rubber, and styrene-butadiene rubber. The mass and volume changes after impregnation are both within 10%, and the volume changes for chloroprene rubber and ethylene propylene rubber are also controlled within 10%. This indicates that the alkylated oligonaphthalenes of Examples 1 and 2, even after prolonged direct contact with rubber-based sealing materials, result in lower swelling levels in the latter, thus preventing them from losing their sealing and leak-preventing functions.

[0116] Table 4

[0117]

[0118] Table 5 below shows the formulations and related properties of the gasoline engine oils of Examples 8-13 and Comparative Examples 5-7. The gasoline engine oils are SAE 0W20 API SP / GF-6 specifications, with a corresponding kinematic viscosity of 5.3-9.3 mm at 100°C. 2 / s.

[0119] The specific testing methods and standards are listed below:

[0120] Kinematic viscosity and viscosity index, flash point and oxidation stability were tested using the methods described above.

[0121] Shear stability: Shear stability was determined using a tapered roller bearing testing machine according to the SH / T 0845 standard. After 20 hours of testing, the kinematic viscosity of the oil samples before and after the test was recorded at 100℃, and the relative viscosity loss Rv (%) was calculated. Rv characterizes the viscosity shear stability of different samples; the lower the Rv, the higher the viscosity shear stability. The formula for calculating Rv is:

[0122] Among them, V S V represents the kinematic viscosity of the engine oil sample at 100°C before the test. E The value represents the kinematic viscosity of the oil sample at 100°C after the test.

[0123] Anti-friction performance: The anti-friction performance was tested using a four-ball testing machine according to the SH / T 0189 standard. After the test, the wear scar diameter of the lower steel ball was measured. The smaller the wear scar diameter, the better the anti-friction performance of the sample. The average value of the wear scar diameter of the three lower steel balls was used to evaluate the anti-friction performance of the oil sample.

[0124] The four-ball test conditions are as follows: load: 392 N (40 kgf); spindle speed: 1200 r / min; test time: 60 min; test temperature: 75℃.

[0125] Evaporation loss: The NOACK evaporation loss test was performed at 100°C for 24 h using the standard ASTM D5800 method, and the corresponding percentage of evaporation loss (mass fraction) was recorded.

[0126] Continuous coking plate test: The thermal oxidation stability was tested using the crankcase simulation test according to standard SH / T 0300. The oil tank temperature was 150℃, the plate temperature was 310℃, and the test time was 6 hours. The thermal oxidation stability of the engine oil sample was evaluated by measuring the weight of the deposits on the metal plate.

[0127] Low-temperature Brinell viscosity: The Brinell viscosity of the engine oil sample at -40℃ was tested using the standard GB / T11145 Brinell viscosity determination method. Low-temperature dynamic viscosity (CCS): The viscosity of the engine oil sample at -35℃ was tested using the standard GB / T 6538 engine oil apparent viscosity cold start simulator method.

[0128] The preparation method of gasoline engine oil is as follows: Take the alkyl naphthalene oligomers of Examples 1 and 2 or the commercial alkyl naphthalene products of Comparative Examples 3 and 4 and mix them evenly with base oils such as mPAO3.5 and PAO6. Stir until clear and transparent, and at the same time turn on the heating. Under the heating condition of 40°C, add the thickener and various functional additives to the base oil, mix evenly, and stir at a stirring speed of 120 r / min for 0.5 h to obtain gasoline engine oil.

[0129] The functional additives used in the gasoline engine oil are fixed at 8.3 parts by weight, specifically including: 3.5 parts by weight of calcium petroleum sulfonate, 1.5 parts by weight of boronized polyisobutylene succinimide, 1.3 parts by weight of N-phenylnaphthylamine, and 2 parts by weight of monooleate glyceryl ester.

[0130] Table 5

[0131]

[0132]

[0133] The test results for the oxidation stability, thermal oxidation stability, shear stability, evaporation loss, and friction properties of the gasoline engine oils in Examples 8-13 and Comparative Examples 5-7 are shown in Table 5.

[0134] As shown in Tables 5 and 6 below, after adding the alkylated oligonaphthalene from Examples 1 and 2, the gasoline engine oil exhibited lower evaporation loss, higher oxidation stability, and a very significant improvement in thermal oxidation stability. The deposit quality in the coking plate test was significantly reduced, and the anti-friction performance was also improved to some extent. The corresponding average wear scar diameter in the four-ball test was also lower. Compared to the commercially available engine oil ESP X2 0W20 of Comparative Example 7, the gasoline engine oils of Examples 8-13 showed superior oxidation stability, evaporation loss, and anti-friction performance, while those of Examples 8-11 exhibited superior thermal oxidation stability.

[0135] For viscosity index, CCS, low-temperature Brinell viscosity, and shear stability, the relationship with high molecular weight thickeners in gasoline engine oil formulations is greater. Gasoline engine oils prepared using methacrylate copolymers Vis3-510 exhibit significantly better low-temperature performance than those prepared using high-viscosity metallocene polyalphaolefins, reflected in lower CCS and low-temperature Brinell viscosity, which is beneficial for the fluidity of gasoline engine oils at extreme low temperatures. Correspondingly, the higher viscosity index facilitates cold starts at extreme low temperatures. However, the shear stability of gasoline engine oils prepared with Vis3-510 is significantly inferior to that prepared with high-viscosity metallocene polyalphaolefins. This conclusion can be drawn from the performance comparison analysis of Examples 8-11 and Comparative Examples 5 and 6. Therefore, to balance the low-temperature performance and shear stability of gasoline engine oils, it is advisable to consider using a mixture of two different types of thickeners, Vis3-510 and mPAO1000, as in Examples 12 and 13.

[0136] Table 6

[0137]

[0138] Table 7 below shows the formulations and related properties of the diesel engine oils in Examples 14-17. The diesel engine oils are SAE 0W40 APICK-4 specifications, with a corresponding kinematic viscosity of 12.5-16.3 mm at 100°C. 2 / s.

[0139] Preparation method of diesel engine oil: Take the alkyl naphthalene oligomers of Examples 1 and 2 or the commercial alkyl naphthalene products of Comparative Examples 3 and 4 and mix them evenly with mPAO3.5 base oil. Stir until clear and transparent, and at the same time turn on the heating. Under the heating condition of 40°C, add the thickener and various functional additives to the base oil and mix evenly. Stir at a stirring speed of 120 r / min for 0.5 h to obtain diesel engine oil.

[0140] The functional additives used in the diesel engine oil are fixed at 15 parts by weight, specifically including: 3.5 parts by weight of alkyl salicylate calcium, 3 parts by weight of boronized polyisobutylene succinimide, 2 parts by weight of methyl succinate, 2.5 parts by weight of dimethyl diphenylamine, 1 part by weight of 2,6-di-tert-butyl-p-cresol, and 3 parts by weight of glyceryl monooleate.

[0141] Table 7

[0142]

[0143]

[0144] The oxidation stability, thermal oxidation stability, shear stability, evaporation loss, and friction properties of the diesel engine oils in Examples 14-17 are shown in Table 7. Analysis of Examples 14-17 in Tables 7 and 8 below shows that adding the alkylated oligonaphthalenes of Examples 1 and 2 as base oils improves the oxidation stability, evaporation loss, and thermal oxidation stability of the diesel engine oils. However, replacing part of the alkylated oligonaphthalene base oils with commercially available alkylnaphthalenes from Comparative Examples 3 and 4 results in a decrease in these properties.

[0145] Table 8

[0146]

[0147] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. This document has described the present invention in detail with reference to the foregoing specific embodiments; however, those skilled in the art can still modify the technical solutions described in the embodiments or make equivalent substitutions for some of them. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A base oil composition comprising: an API-IV base oil in a mass fraction of 75-97%; and an alkylated naphthalene oligomer in a mass fraction of 3-25%, preferably, the API-IV base oil being a polyalphaolefin.

2. The base oil composition according to claim 1, wherein the preparation of the alkylated naphthalene oligomer comprises: Naphthalene is used as a raw material to obtain oligo-naphthalene through an oligomerization reaction, and then alkylated naphthalene oligomers are obtained through an alkylation reaction with linear α-olefins. The oligomerization and alkylation reactions of naphthalene compounds are carried out using chloroaluminate ionic liquid catalysis. An oxidant is used in the oligomerization and alkylation processes.

3. The base oil composition according to claim 1, wherein the alkylated naphthalene oligomer comprises one or more compounds from the group consisting of: monosubstituted alkyl dinaphthalene, disubstituted alkyl dinaphthalene, trisubstituted alkyl dinaphthalene, monosubstituted alkyl trimenaphthalene, disubstituted alkyl trimenaphthalene, trisubstituted alkyl trimenaphthalene, monosubstituted alkyl tetranaphthalene, disubstituted alkyl tetranaphthalene, monosubstituted alkyl pentanaphthalene, and disubstituted alkyl pentanaphthalene; Furthermore, the alkylated naphthalene oligomer also comprises one or more compounds from the following group: monosubstituted alkyl naphthalene, disubstituted alkyl naphthalene, trisubstituted alkyl naphthalene, monosubstituted alkyl anthracene, disubstituted alkyl anthracene, monosubstituted alkyl phenanthrene, disubstituted alkyl phenanthrene, monosubstituted alkyl 1-phenyl naphthalene, disubstituted alkyl 1-phenyl naphthalene, monosubstituted alkyl 2-phenyl naphthalene, and disubstituted alkyl 2-phenyl naphthalene.

4. The base oil composition according to claim 1, wherein the polyalphaolefin has a kinematic viscosity of 1 to 10 mm at 100°C. 2 Preferably, the kinematic viscosity of the polyalphaolefin at 100°C is 2–8 mm / s. 2 / s, and more preferably, the kinematic viscosity of the polyalphaolefin at 100°C is 2–6 mm. 2 / s; Furthermore, the polyalphaolefin is selected from metallocene polyalphaolefins, non-metallocene polyalphaolefins, or a mixture of both; wherein, The metallocene polyalphaolefin is prepared by catalyzing the polymerization of alpha-olefins using a metallocene catalyst system, and the non-metallocene polyalphaolefin is prepared by catalyzing the polymerization of alpha-olefins using a non-metallocene catalyst system.

5. An internal combustion engine oil, comprising: The base oil composition according to any one of claims 1-4 has a mass fraction of 75-95%; as well as Tackifier, in parts by weight 1 to 10%.

6. The internal combustion engine oil according to claim 5, wherein the internal combustion engine oil further comprises: Internal combustion engine oil functional additives, with a mass fraction of 5-20%.

7. The internal combustion engine oil according to claim 5, wherein the viscosity modifier is selected from high-viscosity metallocene polyalphaolefins or methacrylate copolymers or combinations thereof, and the high-viscosity metallocene polyalphaolefin has a kinematic viscosity ≥100 mmHg at 100°C. 2 / s.

8. The internal combustion engine oil according to claim 6, wherein the functional additive of the internal combustion engine oil is at least one of detergent, dispersant, antioxidant, and friction modifier; The detergent is selected from at least one of petroleum sulfonates, synthetic sulfonates, sulfurized alkylphenol salts, naphthenates, and alkyl salicylates; The dispersant is selected from at least one of succinate, succinimide, ashless phosphonate, boronized polyisobutylene succinimide, and phenolic amine; The antioxidant is selected from at least one of 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butyl-4-ethylphenol, 2,4-dimethyl-6-tert-butylphenol, alkylated diphenylamine, N-alkylnaphthylamine, N-phenylnaphthylamine and molybdate; The friction modifier is selected from at least one of fatty acids, fatty alcohols, fatty amines and / or their derivatives and organomolybdenum compounds.

9. A method for preparing the internal combustion engine oil according to any one of claims 5-8, comprising: The base oil composition, thickener, and internal combustion engine oil functional additive described in any one of claims 1-4 are mixed evenly and stirred until clear and transparent to obtain the final product.

10. An internal combustion engine using the internal combustion engine oil according to any one of claims 5-8.

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