Low ash low sulphur automotive lubricating oil and method for its preparation

Abstract

The application provides a low-ash and low-sulfur lubricating oil for vehicles and a preparation method thereof, and belongs to the technical field of lubricating oils; the application forms an amphiphilic molecular structure by modifying polyisobutylene succinic anhydride and polyamide amine, forms a supramolecular ordered film through self-assembly, captures combustion products and carbon deposition particles, reduces the generation of ash and deposits, and thus meets the performance requirements of low-ash and low-sulfur lubricating oil; the reversible reaction of N-(2-aminoethyl) maleimide and 2,5-bis(aminomethyl) furan is used to endow the molecule with the self-repairing ability of bond breaking-recombination, and to repair the microcracks of the lubricating system; for anti-wear agents, MXene is activated by UV / O3, and is modified in multiple steps by combining tributyl borate and fluoroalkyl silane, so as to endow the anti-wear agents with a low friction coefficient, high thermal stability and excellent dispersing performance, and to provide persistent lubrication and effective protection under high temperature and high pressure conditions, and to realize persistent lubrication protection under extreme working conditions.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil technology, and relates to a low-ash, low-sulfur automotive lubricating oil and its preparation method. Background Technology

[0002] In the context of the rapid development of the automotive industry, the quality and performance of lubricating oils are receiving increasing attention. As a key medium for the normal operation of engines, lubricating oil is not only responsible for reducing friction and wear, but also directly affects the engine's efficiency, durability, and environmental performance. With the increasing global demands for environmental protection, the formulation and composition of automotive lubricating oils are gradually evolving, especially in reducing ash and sulfur content, which has become an important research direction in the industry.

[0003] Traditional automotive lubricants are typically mineral oil-based, with various additives added to enhance their anti-wear, friction-reducing, and cleaning properties. These additives are diverse, including antioxidants, detergents, and extreme pressure agents, designed to improve the overall performance of the lubricant. However, these traditional additives often lead to high ash content in the lubricant during use. Ash is a solid residue produced during combustion or oxidation of the lubricant. Over time, the accumulation of ash not only affects the oil's cleaning properties but can also lead to the formation of carbon deposits and build-up inside the engine, impacting engine performance and lifespan. The presence of these carbon deposits can cause reduced engine power, decreased fuel efficiency, and even serious mechanical failures.

[0004] Furthermore, many traditional lubricating oils have a high sulfur content, especially under high-temperature operating conditions. Sulfur oxidation can lead to corrosion and deposit formation, reducing the efficiency and safety of the lubricating oil. The sulfur oxides produced after combustion of high-sulfur lubricating oils not only pollute the environment but can also cause corrosion of engine components, shortening their service life.

[0005] In recent years, synthetic PAO and other base oils have gained popularity due to their superior temperature stability and low volatility. These synthetic base oils exhibit better oxidation resistance and thermal stability at high temperatures, which can improve the performance of lubricating oils to some extent. However, even with the use of synthetic base oils, current technologies still face the challenge of further reducing ash and sulfur content. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a low-ash, low-sulfur automotive lubricant and its preparation method. This invention designs and modifies polyisobutylene succinic anhydride amphiphilic molecules to form a supramolecular ordered film on the metal surface, reducing friction and wear while simultaneously capturing combustion products and carbon deposits, meeting the demand for low-ash, low-sulfur lubricants and extending engine life. Through the introduction of polyamide amines and multi-step chemical modification, the polarity, dispersibility, and detergency of the molecules are enhanced, achieving efficient capture of acidic and polar impurities and preventing deposit formation. The reaction of N-(2-aminoethyl)maleimide with 2,5-bis(aminomethyl)furan endows the molecules with a self-healing ability of "bond breaking and recombination," repairing microscopic cracks in the lubrication system. UV / O3 activation and tributyl borate modification of the MXene material surface reduce the coefficient of friction and enhance thermal stability. Simultaneously, the introduction of long-chain fluorine groups through fluorination with fluoroalkylsilanes endows the material with extremely low surface energy, excellent high-temperature resistance, and good lubricant dispersion stability, achieving long-lasting lubrication protection under extreme operating conditions.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a low-ash, low-sulfur automotive lubricating oil, the method comprising:

[0009] S1: Polyisobutylene succinic anhydride was dispersed in toluene, and after stirring and dispersion, polyamide amine was added to react and a primary amphiphilic polymer backbone was obtained.

[0010] S2: The primary amphiphilic polymer backbone is reacted with N-(2-aminoethyl)maleimide and then 2,5-bis(aminomethyl)furan is added for reaction. The reaction solution G is obtained by cooling and then p-methylbenzaldehyde is added to obtain a biomimetic supramolecular self-assembled detergent.

[0011] S3: Ti3C2TxMXene powder was treated with a UV / O3 processor to obtain pretreated powder; it was then reacted with tributyl borate to obtain partially borated modified MXene powder;

[0012] S4: Partially boronized MXene powder and fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane were reacted to obtain a modified MXene-based anti-wear and friction-reducing agent.

[0013] S5: A biomimetic supramolecular self-assembly detergent and a modified MXene-based anti-wear and friction-reducing agent are dispersed in a synthetic PAO, and an antioxidant and defoamer are added and mixed evenly to obtain a low-ash, low-sulfur automotive lubricating oil.

[0014] Specifically, S1: Polyisobutylene succinic anhydride is dispersed in toluene and stirred at a constant temperature to obtain dispersion A. A toluene solution of polyamide amine is added dropwise to obtain reaction solution B. After stirring and reacting, the primary amphiphilic polymer skeleton is obtained by rotary evaporation under reduced pressure.

[0015] S2: The primary amphiphilic polymer backbone is dispersed in anhydrous xylene and stirred at a constant temperature to obtain dispersion C. A xylene solution of N-(2-aminoethyl)maleimide is added dropwise to obtain reaction solution D. After stirring and reacting, the temperature is increased to obtain reaction solution E. A toluene solution of 2,5-bis(aminomethyl)furan is added dropwise to obtain reaction solution F. After stirring and reacting, the temperature is decreased to obtain reaction solution G. p-Toluene is added and the reaction is stirred and reacted. The mixture is then rotary evaporated and dried to obtain a biomimetic supramolecular self-assembled detergent.

[0016] S3: Ti3C2TxMXene powder was treated with a UV / O3 processor to obtain pretreated powder; a toluene dispersion of the pretreated powder with a mass fraction of 1-3 wt.% was prepared, and a toluene solution of tributyl borate was added to obtain reaction solution H. The reaction was carried out under sulfuric acid catalysis and constant temperature stirring. After centrifugation, washing, and drying, partially borated modified MXene powder was obtained.

[0017] S4: Partially boronized modified MXene powder and fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane were dispersed in toluene / water solution to obtain reaction solution I. The reaction was carried out at constant temperature, and the mixture was filtered, washed and dried to obtain modified MXene-based anti-wear and friction reducing agent.

[0018] S5: A biomimetic supramolecular self-assembly detergent and a modified MXene-based anti-wear and friction-reducing agent are dispersed in a synthetic PAO, and an antioxidant and defoamer are added and mixed evenly to obtain a low-ash, low-sulfur automotive lubricating oil.

[0019] As a preferred embodiment of the present invention, in step S1, the mass fraction of the polyisobutylene succinic anhydride dispersed in toluene is 20-30 wt.%, for example, it can be 20 wt.%, 21 wt.%, 22 wt.%, 23 wt.%, 24 wt.%, 25 wt.%, 26 wt.%, 27 wt.%, 28 wt.%, 29 wt.%, or 30 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0020] In some optional embodiments, the polyisobutylene succinic anhydride is dispersed in toluene and stirred at a constant temperature of 120-130°C to obtain dispersion A, for example, 120°C, 121°C, 122°C, 123°C, 124°C, 125°C, 126°C, 127°C, 128°C, 129°C or 130°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0021] In some optional embodiments, the mass fraction of the polyamidoamine toluene solution is 10-20 wt.%, for example, it can be 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%, 14 wt.%, 15 wt.%, 16 wt.%, 17 wt.%, 18 wt.%, 19 wt.%, or 20 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0022] In some optional embodiments, the molar ratio of polyisobutylene succinic anhydride to polyamide amine is 1:(0.3-0.6), for example, it can be 1:0.3, 1:0.33, 1:0.36, 1:0.39, 1:0.42, 1:0.45, 1:0.48, 1:0.51, 1:0.54 or 1:0.6, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0023] In some optional embodiments, the reaction solution B is stirred for 4-5 hours, for example, 4 hours, 4.1 hours, 4.2 hours, 4.3 hours, 4.4 hours, 4.5 hours, 4.6 hours, 4.7 hours, 4.8 hours, 4.9 hours or 5 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] As a preferred embodiment of the present invention, in step S2, the mass fraction of the primary amphiphilic polymer backbone dispersed in anhydrous xylene is 15-25 wt.%, for example, it can be 15 wt.%, 16 wt.%, 17 wt.%, 18 wt.%, 19 wt.%, 20 wt.%, 21 wt.%, 22 wt.%, 23 wt.%, 24 wt.%, or 25 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0025] In some optional embodiments, the primary amphiphilic polymer skeleton is dispersed in anhydrous xylene and stirred at a constant temperature of 80-90°C to obtain dispersion C. For example, the temperature can be 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, or 90°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] In some optional embodiments, the mass fraction of the N-(2-aminoethyl)maleimide xylene solution is 10-15 wt.%, for example, it can be 10 wt.%, 10.5 wt.%, 11 wt.%, 11.5 wt.%, 12 wt.%, 12.5 wt.%, 13 wt.%, 13.5 wt.%, 14 wt.%, 14.5 wt.%, or 15 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0027] In some alternative embodiments, the molar ratio of the primary amphiphilic polymer backbone to N-(2-aminoethyl)maleimide is 1:(0.1-0.2), for example, it can be 1:0.1, 1:0.11, 1:0.12, 1:0.13, 1:0.14, 1:0.15, 1:0.16, 1:0.17, 1:0.18, 1:0.19 or 1:0.2, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0028] In some optional embodiments, the reaction time of the reaction solution D is 1-2 hours, for example, it can be 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours or 2 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0029] In some optional embodiments, the reaction solution D is stirred and then heated to 110-120°C to obtain reaction solution E. For example, it can be 110°C, 111°C, 112°C, 113°C, 114°C, 115°C, 116°C, 117°C, 118°C, 119°C, or 120°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] In some optional embodiments, the toluene solution of 2,5-bis(aminomethyl)furan has a mass fraction of 5-10 wt.%, for example, 5 wt.%, 5.5 wt.%, 6 wt.%, 6.5 wt.%, 7 wt.%, 7.5 wt.%, 8 wt.%, 8.5 wt.%, 9 wt.%, 9.5 wt.%, or 10 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0031] In some alternative embodiments, the molar ratio of N-(2-aminoethyl)maleimide to 2,5-bis(aminomethyl)furan is 1:(1-1.2), for example, it can be 1:1, 1:1.02, 1:1.04, 1:1.06, 1:1.08, 1:1.1, 1:1.12, 1:1.14, 1:1.16, 1:1.18 or 1:1.2, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0032] In some optional embodiments, the reaction time of the reaction solution F is 2-3 hours, for example, it can be 2 hours, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours, 2.5 hours, 2.6 hours, 2.7 hours, 2.8 hours, 2.9 hours or 3 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] In some optional embodiments, the reaction solution F is cooled to 60-70°C after stirring to obtain reaction solution G. For example, it can be 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C or 70°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] In some optional embodiments, the amount of p-methylbenzaldehyde fed is 5-10% of the mass of the primary amphiphilic polymer backbone, for example, it can be 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0035] In some optional embodiments, after adding p-methylbenzaldehyde to the reaction solution G, the reaction is stirred for 1-2 hours, for example, 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, or 2 hours, but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] As a preferred technical solution of the present invention, in step S3, the ozone concentration of the Ti3C2TxMXene powder is 50-100ppm when treated with a UV / O3 processor. For example, it can be 50ppm, 55ppm, 60ppm, 65ppm, 70ppm, 75ppm, 80ppm, 85ppm, 90ppm, 95ppm or 100ppm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] In some optional embodiments, the Ti3C2TxMXene powder is processed with a UV / O3 processor for 30-50 minutes, for example, 30 minutes, 32 minutes, 34 minutes, 36 minutes, 38 minutes, 40 minutes, 42 minutes, 44 minutes, 46 minutes, 48 ​​minutes or 50 minutes, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0038] In some optional embodiments, the mass fraction of the toluene dispersion of the pretreated powder is 1-3 wt.%, for example, it can be 1 wt.%, 1.2 wt.%, 1.4 wt.%, 1.6 wt.%, 1.8 wt.%, 2 wt.%, 2.2 wt.%, 2.4 wt.%, 2.6 wt.%, 2.8 wt.%, or 3 wt.%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0039] In some optional embodiments, the mass fraction of the tributyl borate toluene solution is 5-10 wt.%, for example, it can be 5 wt.%, 5.5 wt.%, 6 wt.%, 6.5 wt.%, 7 wt.%, 7.5 wt.%, 8 wt.%, 8.5 wt.%, 9 wt.%, 9.5 wt.%, or 10 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0040] In some optional embodiments, the mass ratio of the pretreatment powder to tributyl borate is 1:(2-4), for example, it can be 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, 1:3.2, 1:3.4, 1:3.6, 1:3.8 or 1:4, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0041] In some optional embodiments, the temperature of the isothermal reaction of the reaction solution H is 60-80°C, for example, it can be 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0042] In some optional embodiments, the reaction time of the reaction solution H at a constant temperature is 3-4 hours, for example, 3 hours, 3.1 hours, 3.2 hours, 3.3 hours, 3.4 hours, 3.5 hours, 3.6 hours, 3.7 hours, 3.8 hours, 3.9 hours or 4 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] As a preferred technical solution of the present invention, in step S4, the mass ratio of the partially borated modified MXene powder to the fluoroalkylsilane is 1:(0.8-1.2), for example, it can be 1:0.8, 1:0.84, 1:0.88, 1:0.92, 1:0.96, 1:1, 1:1.04, 1:1.08, 1:1.12, 1:1.16 or 1:1.2, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0044] In some alternative embodiments, the partially borated MXene powder has a mass fraction of 0.8-1.2 wt.% in toluene / aqueous solution, for example, 0.8 wt.%, 0.84 wt.%, 0.88 wt.%, 0.92 wt.%, 0.96 wt.%, 1 wt.%, 1.04 wt.%, 1.08 wt.%, 1.12 wt.%, 1.16 wt.%, or 1.2 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0045] In some optional embodiments, the temperature of the isothermal reaction of the reaction solution I is 80-100°C, for example, it can be 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, 92°C, 94°C, 96°C, 98°C or 100°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0046] In some optional embodiments, the reaction time of the reaction solution I at constant temperature is 2-3 hours, for example, it can be 2 hours, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours, 2.5 hours, 2.6 hours, 2.7 hours, 2.8 hours, 2.9 hours or 3 hours, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0047] As a preferred technical solution of the present invention, in step S5, the amount of antioxidant added is 0.1-0.5% of the mass of synthesized PAO, for example, it can be 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45% or 0.5%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0048] The antioxidant is any one or a combination of two of alkylated diphenylamine and IRGANOXL135;

[0049] In some optional embodiments, the defoamer is SAG47, and the amount of defoamer added is 0.01-0.05% of the mass of the synthesized PAO, for example, it can be 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045% or 0.05%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0050] Secondly, the present invention provides a low-ash, low-sulfur automotive lubricant. The low-ash, low-sulfur automotive lubricant comprises synthetic PAO, a biomimetic supramolecular self-assembled detergent, and a modified MXene-based anti-wear and friction-reducing agent, wherein the mass ratio of the synthetic PAO, the biomimetic supramolecular self-assembled detergent, and the modified MXene-based anti-wear and friction-reducing agent is 100:(3-5):(0.3-0.8).

[0051] Inspired by the structure and functional properties of biological and cell membranes, this invention utilizes their bilayer structure and self-assembly mechanism to construct stable supramolecular ordered films through the spontaneous arrangement of head-to-tail amphiphilic molecules on metal surfaces or oil-oil interfaces. The formation of this ordered film not only effectively reduces friction and wear at metal interfaces but also enhances the capture of combustion products, carbon deposits, and acidic impurities, thereby significantly improving the overall performance of lubricating oils. To achieve this goal, this invention selects polyisobutylene succinic anhydride as the base material and, leveraging its unique molecular structure, uses chemical modification to regulate its functionality.

[0052] Polyisobutylene succinic anhydride is a molecule with significant amphiphilic properties. Its hydrophobic polyisobutylene segments form long-chain hydrocarbon structures, endowing it with excellent lubricating properties; while the hydrophilic anhydride groups are active sites, which can be further modified through chemical reactions. However, polyisobutylene succinic anhydride also has certain limitations: its strong hydrophobicity makes it difficult to achieve stable dispersion in lubricating oils. Especially under high temperature and high pressure conditions, when used alone, polyisobutylene succinic anhydride is difficult to effectively remove carbon deposits and acidic combustion products generated in the engine lubrication system, thus limiting the detergency and antioxidant properties of the lubricating oil.

[0053] To overcome this problem, polyamide amine is introduced as a modifier in this invention. The molecular structure of polyamide amine contains multiple primary and secondary amino groups, which have high nucleophilicity and can undergo a ring-opening reaction with the anhydride group of polyisobutylene succinic anhydride. During the reaction, the anhydride group undergoes ring-opening, generating an amide bond and a carboxylate or carboxylic acid ester. This chemical reaction not only endows the molecule with higher chemical stability but also generates a modified molecule with amphiphilic properties. Its molecular structure retains the hydrophobic polyisobutylene segments while introducing hydrophilic amide and carboxylic acid groups, thus giving the molecule significant amphiphilicity.

[0054] The performance of polyisobutylene succinic anhydride was optimized by introducing polyamide amine. First, the hydrophobic long-chain polyisobutylene moiety continues to provide its inherent lubricating properties, enabling the modified molecules to form a low-friction molecular film at the metal interface, significantly reducing the coefficient of friction and wear rate. Second, the newly generated amide and carboxylic acid groups significantly increase the polarity of the molecules, allowing for more uniform dispersion in the lubricating oil matrix and preventing molecular aggregation or precipitation. Furthermore, the modified amphiphilic molecular structure can form a stable self-assembly system in the lubricating oil. This system can effectively capture acidic and polar products generated during engine combustion, thereby preventing these combustion products from depositing on the metal surface.

[0055] It is worth noting that the amphiphilic molecular structure also plays an important cleaning role in the combustion environment. By capturing acidic and polar combustion products, the modified molecules can reduce the formation of ash in lubricating oil, while preventing the aggregation and deposition of carbon deposits. The amine-modified polyisobutylene succinic anhydride system used in this invention produces very little inorganic residue under high-temperature combustion products, thus achieving "low ash content". Simultaneously, it enhances alkali reserve capacity through intermolecular hydrogen bonding, π-π stacking, and polar interactions.

[0056] Although primary amphiphilic polymer skeletons possess certain detergency properties in lubricating oils, their intermolecular forces are weak, relying mainly on simple physical adsorption between polar groups and combustion products, making it difficult to form stable bonds with complex combustion products. Especially given the diverse and complex types of impurities generated during engine combustion, the primary amphiphilic polymer skeleton alone is insufficient for efficient capture and dispersion. Therefore, to further improve the performance of the detergent, this invention introduces various functional molecules for gradual modification, enhancing its intermolecular interactions and its ability to capture combustion products.

[0057] First, this invention introduces N-(2-aminoethyl)maleimide for chemical modification. The molecular structure of N-(2-aminoethyl)maleimide contains a primary amino group and a five-membered cyclic imide group. The amino group exhibits strong nucleophilicity, enabling it to bind with the carboxylic acid group or residual anhydride group in the primary amphiphilic polymer backbone via an amidation reaction. This reaction not only generates a chemically stable amide bond but also introduces a maleimide structure into the molecule. As a strongly polar structural unit, maleimide significantly enhances the polarity of the molecule, thereby improving its ability to capture polar impurities in combustion products. Furthermore, the rigid structure of maleimide helps improve the intermolecular order, further optimizing its dispersibility and stability in lubricating oils.

[0058] Next, this invention further enhances the detergency of the primary amphiphilic polymer backbone by introducing the functionally modified molecule 2,5-bis(aminomethyl)furan. The 2,5-bis(aminomethyl)furan molecule contains two reactive amine groups, which can undergo amidation reactions with the remaining carboxylic acid groups in the amphiphilic polymer backbone to form more amide bonds. Simultaneously, the furan group is introduced into the molecular structure, endowing the detergent molecule with stronger functionality. Due to its conjugated structure, the furan ring has an abundant π-electron cloud distribution, a characteristic that allows it to form stable interactions with aromatic compounds or other conjugated molecules in combustion products through π-π stacking interactions. π-π interactions not only enhance the detergent's ability to capture combustion products but also improve its intermolecular forces in lubricating oil, enabling the detergent to more effectively disperse combustion products and prevent their deposition on metal surfaces.

[0059] Furthermore, in the multi-step chemical modification of detergents, this invention utilizes N-(2-aminoethyl)maleimide and 2,5-bis(aminomethyl)furan via a reversible Diels-Alder reaction, enabling the molecules to undergo bond breaking and recombination within a certain temperature range, thereby forming a partially reversible cross-linked network. When microcracks or localized wear occur in the lubricating oil system during operation, heating or applying external energy to trigger the reverse Diels-Alder reaction can break the cross-links, and upon subsequent cooling or recoordination, DA adducts can be generated to repair or heal the microcracks. In addition, the DA bond between the furan ring and maleimide, when in contact with the external friction interface, can also increase the compatibility and toughness of the composite film, further enhancing the lubricating oil's protective ability against the friction pair surface, extending its service life, and reducing high-temperature deposition.

[0060] To further enhance the electronic properties and intermolecular interactions of the detergent, this invention also introduces functionalization modification of p-methylbenzaldehyde. The aldehyde group in the p-methylbenzaldehyde molecule can undergo a Schiff base reaction with the residual amino group in the detergent molecule to generate a polar and rigid imine bond. The imine bond is not only structurally stable but also has a high electron cloud density, a characteristic that enables it to effectively adsorb polar or charged particles in combustion products. Furthermore, the presence of the imine bond further strengthens the intermolecular interactions and improves the overall three-dimensional stability of the molecule. The methyl substituents in p-methylbenzaldehyde also impart a certain degree of hydrophobicity to the molecule. This localized hydrophobicity, combined with the amphiphilic structure, allows the detergent to better adapt to the hydrophobic environment of lubricating oil, thereby achieving uniform dispersion.

[0061] Through the above multi-step modification, the generated detergent molecules not only possess stronger intermolecular forces but also spontaneously form a stable supramolecular network structure in lubricating oil. This supramolecular network can synergistically capture combustion products, carbon deposits, and acidic impurities through intermolecular hydrogen bonds, π-π stacking interactions, and electrostatic interactions, effectively preventing combustion products from depositing on metal surfaces. Furthermore, the π-electron cloud characteristics of the furan ring and the polarity of the Schiff base structure further enhance the detergent's adsorption capacity for combustion products. Through these synergistic effects, the modified detergent can significantly improve the cleaning performance of lubricating oil, reduce ash generation, and extend engine life.

[0062] This invention introduces Ti3C2TxMXene powder as the core component of a lubricating oil anti-wear and friction-reducing agent, and optimizes its performance through multi-step modification, overcoming the limitations of the original material in practical applications. MXene, as a two-dimensional metal carbide with high specific surface area, excellent conductivity, and abundant surface chemical activity, contains a large number of active sites such as hydroxyl groups, fluorine groups, and oxides on its surface. However, these active sites easily induce particle agglomeration in the lubricating oil matrix, resulting in poor dispersion stability. Furthermore, MXene's anti-wear and friction-reducing performance under high temperature and high pressure conditions is also insufficient.

[0063] To improve its dispersibility and lubrication properties, this invention first activates the MXene powder surface through UV / O3 treatment. The synergistic effect of ultraviolet light and ozone oxidizes the hydroxyl and fluorine groups on the MXene surface, generating more active sites, while removing some weakly bound surface groups and stabilizing the surface chemical structure of MXene. The activated MXene exhibits higher chemical reactivity, providing an ideal reaction platform for subsequent functionalization modifications, while also improving its dispersibility in lubricating oils and preventing particle agglomeration.

[0064] Building upon surface activation, this invention further introduces tributyl borate to borate MXene, significantly enhancing its anti-wear properties. The boron in tributyl borate undergoes esterification with the hydroxyl groups on the MXene surface, forming stable boron-oxygen bonds. This boron oxide structure exhibits a low coefficient of friction, enabling the formation of a lubricating film on the surface of metal friction pairs, thereby effectively reducing the coefficient of friction and minimizing mechanical wear. Furthermore, the borate modification further stabilizes the surface chemical structure of MXene, enhancing its thermal stability under high temperature and high shear conditions, preventing material degradation or failure under extreme operating conditions. The borate-treated MXene surface is smoother, exhibiting improved compatibility with the lubricating oil matrix and demonstrating better dispersion stability, laying the foundation for its efficient application in lubricating oils.

[0065] Although boronizing significantly improves the anti-wear properties of MXene, its interfacial lubrication capability may still be insufficient under extreme high temperature or extreme pressure conditions. Therefore, this invention further modifies the boronized MXene with 1H,1H,2H,2H-perfluorodecyltriethoxysilane. The fluoroalkylsilane combines with the hydroxyl groups or boron-oxygen bonds on the MXene surface through a hydrolysis-condensation reaction to form silicon-oxygen bonds, while simultaneously introducing long-chain fluoroalkyl groups onto the material surface. Fluoroalkyl groups possess extremely low surface energy and excellent chemical stability; their introduction not only significantly reduces the coefficient of friction of MXene but also enhances its high-temperature resistance, enabling it to maintain stable lubrication capability under extreme operating conditions. Furthermore, the hydrophobicity of the fluoroalkyl groups further improves the dispersibility of MXene in the lubricating oil matrix, ensuring its long-term stability in the lubricating oil.

[0066] This invention also features a synergistic enhancement effect. The biomimetic supramolecular self-assembly detergent significantly reduces deposits and ash in the lubricating oil by capturing acidic impurities and carbon particles in combustion products; the modified MXene-based anti-wear and friction-reducing agent forms a stable lubricating film on the friction pair surface, reducing the coefficient of friction and wear rate, thereby protecting the metal surface from mechanical damage. The combination of these two functions forms a synergistic mechanism of detergent-anti-wear, improving the overall efficiency of the engine.

[0067] Secondly, the amphiphilic molecular structure of the detergent allows it to disperse uniformly in the lubricating oil matrix and form an adsorption layer on the surface of combustion product particles. This adsorption layer not only captures carbon deposits but also prevents particle aggregation. The surface functionalization of the modified MXene anti-wear agent enhances its compatibility with the lubricating oil, further strengthening the dispersion stability of various components in the lubricating oil. The combination of these two factors ensures the long-term stability of the lubricating oil under high temperature and high pressure conditions, preventing lubricating oil failure caused by the interaction of ash, deposits, and friction particles.

[0068] Boronization with tributyl borate introduces boron-oxygen bonds into the MXene surface. These bonds have a low coefficient of friction, significantly reducing mechanical wear on friction surfaces and improving the thermal stability of MXene. Fluorination with fluoroalkylsilanes further reduces the surface energy of MXene, enhancing its friction-reducing ability under high temperature and extreme pressure conditions, while also improving the material's hydrophobicity and dispersibility in lubricating oils. The boron layer provides basic anti-wear properties, while the fluorination layer provides additional friction-reducing protection under extreme operating conditions. These two modification methods work synergistically to enable MXene materials to exhibit superior anti-wear and friction-reducing properties under various operating conditions.

[0069] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0070] This invention draws inspiration from the self-assembly mechanism of biofilms. By modifying polyisobutylene succinic anhydride, amphiphilic molecules are designed to form supramolecular ordered films on metal surfaces, reducing friction and wear while simultaneously capturing combustion products and carbon deposits. Polyamide amines are introduced to chemically modify the polyisobutylene succinic anhydride, generating a molecular structure with significant amphiphilic properties, improving its dispersibility and detergency. The modified molecules effectively capture acidic and polar combustion products through self-assembly, reducing ash and carbon deposits, thereby meeting the performance requirements of low-ash, low-sulfur lubricating oils and extending engine life.

[0071] This invention utilizes a multi-step chemical modification of a detergent, incorporating N-(2-aminoethyl)maleimide, 2,5-bis(aminomethyl)furan, and p-methylbenzaldehyde to enhance molecular polarity, π-π interactions, and electronic properties, while simultaneously improving dispersibility and stability. The modified detergent self-assembles into a supramolecular network structure, efficiently capturing combustion products and acidic impurities, preventing deposit formation, significantly improving the detergency of lubricating oils, reducing ash generation, and extending engine life.

[0072] This invention also utilizes the reversible Diels-Alder reaction between N-(2-aminoethyl)maleimide and 2,5-bis(aminomethyl)furan, allowing the molecules to undergo bond breaking and recombination within a certain temperature range, thereby forming a partially reversible cross-linked network. When microcracks or localized wear occur in the lubricating oil system during operation, heating or applying external energy to trigger the reverse Diels-Alder reaction can break the cross-links, and upon subsequent cooling or recoordination, DA adducts can be generated to repair or heal the microcracks.

[0073] This invention employs UV / O3 treatment to activate the surface of MXene, generating more active sites and improving its dispersibility. Subsequently, tributyl borate is introduced, forming boron-oxygen bonds through esterification, significantly reducing the coefficient of friction and enhancing thermal stability. To further improve its lubrication capability under extreme conditions, fluorination modification with fluoroalkylsilanes is used to generate silicon-oxygen bonds and introduce long-chain fluoroalkyl groups, endowing MXene with extremely low surface energy and excellent high-temperature resistance, while simultaneously enhancing its hydrophobicity and dispersion stability in lubricating oils, ensuring long-lasting lubrication protection under high temperature and high pressure conditions. Detailed Implementation

[0074] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The embodiments described herein are specific implementations of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limiting the implementation of the present invention or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the content disclosed in the claims and the specification of this application. These technical solutions include technical solutions that employ any obvious substitutions and modifications made to the embodiments described herein.

[0075] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone further purification or processing.

[0076] Example 1

[0077] This embodiment provides a low-ash, low-sulfur automotive lubricating oil and its preparation method. The preparation method of the low-ash, low-sulfur automotive lubricating oil specifically includes the following steps:

[0078] S1: Polyisobutylene succinic anhydride was dispersed in toluene at a mass fraction of 20 wt.% and stirred at a constant temperature of 120℃ to obtain dispersion A. A toluene solution of polyamidoamine with a mass fraction of 10 wt.% was added dropwise to obtain reaction solution B, wherein the molar ratio of polyisobutylene succinic anhydride to polyamidoamine was 1:0.45. After stirring and reacting for 4.5 h, the primary amphiphilic polymer skeleton was obtained by rotary evaporation under reduced pressure.

[0079] S2: The primary amphiphilic polymer backbone was dispersed in anhydrous xylene at a mass fraction of 20 wt.%, and stirred at a constant temperature of 80 °C to obtain dispersion C. A xylene solution of N-(2-aminoethyl)maleimide with a mass fraction of 14 wt.% was added dropwise to obtain reaction solution D, wherein the molar ratio of the primary amphiphilic polymer backbone to N-(2-aminoethyl)maleimide was 1:0.15. After stirring for 1 h, the temperature was raised to 110 °C to obtain reaction solution E, and 8 wt.% of the primary amphiphilic polymer backbone was added dropwise. A toluene solution of 2,5-bis(aminomethyl)furan was used to obtain reaction solution F, wherein the molar ratio of N-(2-aminoethyl)maleimide to 2,5-bis(aminomethyl)furan was 1:1.1. After stirring for 2.8 h, the solution was cooled to 60 °C to obtain reaction solution G. p-Tolualdehyde was added, wherein the amount of p-Tolualdehyde added was 8% of the mass of the primary amphiphilic polymer backbone, and the reaction was continued to be stirred for 1.8 h. The solution was then rotary evaporated and dried to obtain a biomimetic supramolecular self-assembled detergent.

[0080] S3: Ti3C2TxMXene powder was treated with a UV / O3 processor to obtain pretreated powder, wherein the ozone concentration during treatment was 80 ppm and the treatment time was 30 min; a toluene dispersion of 2 wt.% pretreated powder was prepared, and a toluene solution of 5 wt.% tributyl borate was added to obtain reaction solution H, wherein the mass ratio of pretreated powder to tributyl borate was 1:3. The reaction was carried out under sulfuric acid catalysis and at a constant temperature of 60 °C for 3 h with stirring. After centrifugation, washing, and drying, partially borated modified MXene powder was obtained.

[0081] S4: Partially boron-modified MXene powder and fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane were dispersed in toluene / water solution at a mass ratio of 1:1 to obtain reaction solution I, wherein the mass fraction of partially boron-modified MXene powder in toluene was 1 wt.%, and the reaction was carried out at a constant temperature of 95℃ for 2 h. After filtration, washing and drying, modified MXene-based anti-wear and friction reducing agent was obtained.

[0082] S5: A biomimetic supramolecular self-assembled detergent and a modified MXene-based anti-wear and friction-reducing agent are dispersed in a synthetic PAO. An antioxidant, alkylated diphenylamine, is added at a rate of 0.3% of the mass of the synthetic PAO. An antifoamer, SAG47, is added at a rate of 0.04% of the mass of the synthetic PAO. The mixture is then thoroughly mixed to obtain a low-ash, low-sulfur automotive lubricating oil. The mass ratio of the synthetic PAO, the biomimetic supramolecular self-assembled detergent, and the modified MXene-based anti-wear and friction-reducing agent is 100:4:0.5.

[0083] Example 2

[0084] This embodiment provides a low-ash, low-sulfur automotive lubricating oil and its preparation method. The preparation method of the low-ash, low-sulfur automotive lubricating oil specifically includes the following steps:

[0085] S1: Polyisobutylene succinic anhydride was dispersed in toluene at a mass fraction of 25 wt.% and stirred at a constant temperature of 128℃ to obtain dispersion A. A toluene solution of polyamide amine at a mass fraction of 15 wt.% was added dropwise to obtain reaction solution B, wherein the molar ratio of polyisobutylene succinic anhydride to polyamide amine was 1:0.5. After stirring and reacting for 4.8 h, the primary amphiphilic polymer skeleton was obtained by rotary evaporation under reduced pressure.

[0086] S2: The primary amphiphilic polymer backbone was dispersed in anhydrous xylene at a mass fraction of 15 wt.%, and stirred at a constant temperature of 88℃ to obtain dispersion C. A xylene solution of N-(2-aminoethyl)maleimide at a mass fraction of 10 wt.% was added dropwise to obtain reaction solution D, wherein the molar ratio of the primary amphiphilic polymer backbone to N-(2-aminoethyl)maleimide was 1:0.1. After stirring for 1.8 h, the temperature was raised to 115℃ to obtain reaction solution E. A mass fraction of... A 7 wt.% toluene solution of 2,5-bis(aminomethyl)furan was used to obtain reaction solution F, wherein the molar ratio of N-(2-aminoethyl)maleimide to 2,5-bis(aminomethyl)furan was 1:1. After stirring for 2 h, the solution was cooled to 70 °C to obtain reaction solution G. p-Tolualdehyde was added, wherein the amount of p-Tolualdehyde added was 5% of the mass of the primary amphiphilic polymer backbone, and the reaction was continued to be stirred for 1 h. The solution was then rotary evaporated and dried to obtain a biomimetic supramolecular self-assembled detergent.

[0087] S3: Ti3C2TxMXene powder was treated with a UV / O3 processor to obtain pretreated powder, wherein the ozone concentration during treatment was 85 ppm and the treatment time was 40 min; a toluene dispersion of 2.5 wt.% pretreated powder was prepared, and a toluene solution of 8 wt.% tributyl borate was added to obtain reaction solution H, wherein the mass ratio of pretreated powder to tributyl borate was 1:2. The reaction was carried out under sulfuric acid catalysis and at a constant temperature of 70 °C for 4 h with stirring, centrifugation, washing, and drying to obtain partially borated modified MXene powder;

[0088] S4: Partially boron-modified MXene powder and fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane were dispersed in toluene / water solution at a mass ratio of 1:1.1 to obtain reaction solution I, wherein the mass fraction of partially boron-modified MXene powder in toluene was 1.1 wt.%. The reaction was carried out at a constant temperature of 80℃ for 2.5 h, and the mixture was filtered, washed and dried to obtain modified MXene-based anti-wear and friction-reducing agent.

[0089] S5: A biomimetic supramolecular self-assembled detergent and a modified MXene-based anti-wear and friction-reducing agent are dispersed in a synthetic PAO. An antioxidant IRGANOXL135 is added at a rate of 0.1% of the mass of the synthetic PAO. An antifoamer SAG47 is added at a rate of 0.01% of the mass of the synthetic PAO. The mixture is then thoroughly mixed to obtain a low-ash, low-sulfur automotive lubricating oil. The mass ratio of the synthetic PAO, the biomimetic supramolecular self-assembled detergent, and the modified MXene-based anti-wear and friction-reducing agent is 100:4.6:0.3.

[0090] Example 3

[0091] This embodiment provides a low-ash, low-sulfur automotive lubricating oil and its preparation method. The preparation method of the low-ash, low-sulfur automotive lubricating oil specifically includes the following steps:

[0092] S1: Polyisobutylene succinic anhydride was dispersed in toluene at a mass fraction of 28 wt.% and stirred at a constant temperature of 125℃ to obtain dispersion A. A toluene solution of polyamide amine with a mass fraction of 17 wt.% was added dropwise to obtain reaction solution B, wherein the molar ratio of polyisobutylene succinic anhydride to polyamide amine was 1:0.3. After stirring and reacting for 4 hours, the primary amphiphilic polymer skeleton was obtained by rotary evaporation under reduced pressure.

[0093] S2: The primary amphiphilic polymer backbone was dispersed in anhydrous xylene at a mass fraction of 25 wt.%, and stirred at a constant temperature of 90℃ to obtain dispersion C. A xylene solution of N-(2-aminoethyl)maleimide with a mass fraction of 12 wt.% was added dropwise to obtain reaction solution D, wherein the molar ratio of the primary amphiphilic polymer backbone to N-(2-aminoethyl)maleimide was 1:0.2. After stirring for 2 h, the temperature was raised to 118℃ to obtain reaction solution E, and a mass fraction of 5 wt.% was added dropwise. A toluene solution of 2,5-bis(aminomethyl)furan was used to obtain reaction solution F, wherein the molar ratio of N-(2-aminoethyl)maleimide to 2,5-bis(aminomethyl)furan was 1:1.2. After stirring for 2.5 h, the solution was cooled to 65 °C to obtain reaction solution G. p-Tolualdehyde was added, wherein the amount of p-Tolualdehyde added was 10% of the mass of the primary amphiphilic polymer backbone, and the reaction was continued to be stirred for 2 h. The solution was then rotary evaporated and dried to obtain a biomimetic supramolecular self-assembled detergent.

[0094] S3: Ti3C2TxMXene powder was treated with a UV / O3 processor to obtain pretreated powder, wherein the ozone concentration during treatment was 50 ppm and the treatment time was 45 min; a toluene dispersion of 1 wt.% pretreated powder was prepared, and a toluene solution of 7 wt.% tributyl borate was added to obtain reaction solution H, wherein the mass ratio of pretreated powder to tributyl borate was 1:3.5. The reaction was carried out under sulfuric acid catalysis and at a constant temperature of 75 °C for 3.5 h with stirring. After centrifugation, washing, and drying, partially borated modified MXene powder was obtained.

[0095] S4: Partially boronized MXene powder and fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane were dispersed in toluene / water solution at a mass ratio of 1:0.8 to obtain reaction solution I, wherein the mass fraction of partially boronized MXene powder in toluene was 0.8 wt.%. The reaction was carried out at a constant temperature of 90℃ for 2.8 h, and the mixture was filtered, washed and dried to obtain modified MXene-based anti-wear and friction reducing agent.

[0096] S5: A biomimetic supramolecular self-assembled detergent and a modified MXene-based anti-wear and friction-reducing agent are dispersed in a synthetic PAO. An antioxidant, alkylated diphenylamine, is added at a rate of 0.4% of the mass of the synthetic PAO. An antifoamer, SAG47, is added at a rate of 0.05% of the mass of the synthetic PAO. The mixture is then thoroughly mixed to obtain a low-ash, low-sulfur automotive lubricating oil. The mass ratio of the synthetic PAO, the biomimetic supramolecular self-assembled detergent, and the modified MXene-based anti-wear and friction-reducing agent is 100:3:0.8.

[0097] Example 4

[0098] This embodiment provides a low-ash, low-sulfur automotive lubricating oil and its preparation method. The preparation method of the low-ash, low-sulfur automotive lubricating oil specifically includes the following steps:

[0099] S1: Polyisobutylene succinic anhydride was dispersed in toluene at a mass fraction of 30 wt.% and stirred at a constant temperature of 130℃ to obtain dispersion A. A toluene solution of polyamide amine with a mass fraction of 20 wt.% was added dropwise to obtain reaction solution B, wherein the molar ratio of polyisobutylene succinic anhydride to polyamide amine was 1:0.6. After stirring and reacting for 5 hours, the primary amphiphilic polymer skeleton was obtained by rotary evaporation under reduced pressure.

[0100] S2: The primary amphiphilic polymer backbone was dispersed in anhydrous xylene at a mass fraction of 23 wt.%, and stirred at a constant temperature of 85°C to obtain dispersion C. A xylene solution of N-(2-aminoethyl)maleimide at a mass fraction of 15 wt.% was added dropwise to obtain reaction solution D, wherein the molar ratio of the primary amphiphilic polymer backbone to N-(2-aminoethyl)maleimide was 1:0.18. After stirring for 1.5 h, the temperature was raised to 120°C to obtain reaction solution E. A xylene solution of N-(2-aminoethyl)maleimide at a mass fraction of 10 wt.% was added dropwise. A toluene solution of 0.% 2,5-bis(aminomethyl)furan was used to obtain reaction solution F, wherein the molar ratio of N-(2-aminoethyl)maleimide to 2,5-bis(aminomethyl)furan was 1:1.15. After stirring for 3 h, the solution was cooled to 68 °C to obtain reaction solution G. p-Tolualdehyde was added, wherein the amount of p-Tolualdehyde added was 7.5% of the mass of the primary amphiphilic polymer backbone, and the reaction was continued to be stirred for 1.5 h. The solution was then rotary evaporated and dried to obtain a biomimetic supramolecular self-assembled detergent.

[0101] S3: Ti3C2TxMXene powder was treated with a UV / O3 processor to obtain pretreated powder, wherein the ozone concentration during treatment was 100 ppm and the treatment time was 50 min; a toluene dispersion of 3 wt.% pretreated powder was prepared, and a toluene solution of 10 wt.% tributyl borate was added to obtain reaction solution H, wherein the mass ratio of pretreated powder to tributyl borate was 1:4. The reaction was carried out under sulfuric acid catalysis and at a constant temperature of 80 °C for 3.8 h with stirring. After centrifugation, washing, and drying, partially borated modified MXene powder was obtained.

[0102] S4: Partially boron-modified MXene powder and fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane were dispersed in toluene / water solution at a mass ratio of 1:1.2 to obtain reaction solution I, wherein the mass fraction of partially boron-modified MXene powder in toluene was 1.2 wt.%. The reaction was carried out at a constant temperature of 100℃ for 3 h, and the mixture was filtered, washed and dried to obtain modified MXene-based anti-wear and friction-reducing agent.

[0103] S5: A biomimetic supramolecular self-assembled detergent and a modified MXene-based anti-wear and friction-reducing agent are dispersed in a synthetic PAO. An antioxidant IRGANOXL135 is added at a rate of 0.5% of the mass of the synthetic PAO, and an antifoamer SAG47 is added at a rate of 0.025% of the mass of the synthetic PAO. The mixture is then thoroughly mixed to obtain a low-ash, low-sulfur automotive lubricating oil. The mass ratio of the synthetic PAO, the biomimetic supramolecular self-assembled detergent, and the modified MXene-based anti-wear and friction-reducing agent is 100:5:0.6.

[0104] Comparative Example 1

[0105] This comparative example provides a low-ash, low-sulfur automotive lubricant. The difference between this example and Example 1 is that in S5, the mass ratio of synthetic PAO, biomimetic supramolecular self-assembled detergent, and modified MXene-based anti-wear and friction-reducing agent is 100:8:0.5. Other operating steps and process parameters are exactly the same as in Example 1.

[0106] Comparative Example 2

[0107] This comparative example provides a low-ash, low-sulfur automotive lubricant. The difference between this example and Example 1 is that in S5, the mass ratio of synthetic PAO, biomimetic supramolecular self-assembled detergent, and modified MXene-based anti-wear and friction-reducing agent is 100:1:0.5. Other operating steps and process parameters are exactly the same as in Example 1.

[0108] Comparative Example 3

[0109] This comparative example provides a low-ash, low-sulfur automotive lubricant. The difference between this example and Example 1 is that in S5, the mass ratio of synthetic PAO, biomimetic supramolecular self-assembled detergent, and modified MXene-based anti-wear and friction-reducing agent is 100:8:1. Other operating steps and process parameters are exactly the same as in Example 1.

[0110] Comparative Example 4

[0111] This comparative example provides a low-ash, low-sulfur automotive lubricant. The difference between this example and Example 1 is that in S5, the mass ratio of synthetic PAO, biomimetic supramolecular self-assembled detergent, and modified MXene-based anti-wear and friction-reducing agent is 100:8:0.1. Other operating steps and process parameters are exactly the same as in Example 1.

[0112] The performance of the low-ash, low-sulfur automotive lubricants of Examples 1-4 and Comparative Examples 1-4 was tested, and the specific process is as follows:

[0113] The coefficient of friction of the test sample was tested according to ASTM D5707;

[0114] The oxidation stability of the sample was tested according to GB / T12581-2006;

[0115] The total alkalinity of the sample was tested according to SH / T0688-2000;

[0116] The sulfate ash content of the sample was tested according to GB / T2433-2001;

[0117] The test results are shown in Table 1.

[0118] Table 1. Performance test results of low-ash, low-sulfur automotive lubricants in Examples 1-4 and Comparative Examples 1-4

[0119]

[0120] The test results from Example 1 and Comparative Examples 1 and 2 show that when the mass fraction of the biomimetic supramolecular self-assembled detergent is too high, the excess detergent molecules form large micelles that interfere with the formation of the lubricating film, causing the friction coefficient to increase to 0.085; the excess active groups increase the chance of contact with oxygen, resulting in a decrease in oxidation stability to 670h; the excessive amino functional groups in the detergent provide an excessive alkalinity reserve, causing the total base number to increase to 7.0 mgKOH / g; when the mass fraction of the biomimetic supramolecular self-assembled detergent is too low, the insufficient number of self-assembled structures restricts the formation of the protective film, causing the friction coefficient to increase to 0.082; the synergistic antioxidant effect of the detergent is insufficient, resulting in a decrease in oxidation stability to 750h; and the insufficient alkalinity reserve causes the total base number to decrease to 3.5 mgKOH / g.

[0121] The test results from Example 1 and Comparative Examples 3 and 4 show that when the mass fraction of the modified MXene-based anti-wear and friction-reducing agent is too high, the excessive agglomeration of MXene nanosheets leads to an increase in interfacial shear stress, causing the friction coefficient to rise to 0.084; the increase in surface active sites accelerates oxidation, resulting in a decrease in oxidation stability to 780h; and there is no significant effect on the total base number, which remains at 4.7 mgKOH / g. When the mass fraction of the modified MXene-based anti-wear and friction-reducing agent is too low, the insufficient number of nanosheets affects the continuity of the lubricating film, causing the friction coefficient to rise to 0.083; the effect on oxidation stability is relatively small, basically remaining at 876h; and the total base number remains basically unchanged at 4.8 mgKOH / g.

[0122] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a low-ash, low-sulfur automotive lubricating oil, characterized in that, The preparation method includes: S1: Polyisobutylene succinic anhydride was dispersed in toluene, and after stirring and dispersion, polyamide amine was added to react and a primary amphiphilic polymer backbone was obtained. S2: The primary amphiphilic polymer backbone is reacted with N-(2-aminoethyl)maleimide and then 2,5-bis(aminomethyl)furan is added for reaction. The reaction solution G is obtained by cooling and then p-methylbenzaldehyde is added to obtain a biomimetic supramolecular self-assembled detergent. S3: Ti3C2TxMXene powder was treated with a UV / O3 processor to obtain pretreated powder; it was then reacted with tributyl borate to obtain partially borated modified MXene powder; S4: Partially boronized MXene powder and fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane were reacted to obtain a modified MXene-based anti-wear and friction-reducing agent. S5: The biomimetic supramolecular self-assembled detergent and the modified MXene-based anti-wear and friction-reducing agent are dispersed in the synthetic PAO, and antioxidants and defoamers are added and mixed evenly to obtain a low-ash and low-sulfur automotive lubricating oil. The mass ratio of the synthetic PAO, the biomimetic supramolecular self-assembled detergent and the modified MXene-based anti-wear and friction-reducing agent is 100:(3-5):(0.3-0.8).

2. The method for preparing a low-ash, low-sulfur automotive lubricating oil according to claim 1, characterized in that, In S1: the molar ratio of polyisobutylene succinic anhydride to polyamide amine is 1:(0.3-0.6).

3. The method for preparing a low-ash, low-sulfur automotive lubricating oil according to claim 1, characterized in that, In S2: the molar ratio of the primary amphiphilic polymer backbone to N-(2-aminoethyl)maleimide is 1:(0.1-0.2).

4. The method for preparing a low-ash, low-sulfur automotive lubricating oil according to claim 1, characterized in that, In S2: the molar ratio of N-(2-aminoethyl)maleimide to 2,5-bis(aminomethyl)furan is 1:(1-1.2).

5. The method for preparing a low-ash, low-sulfur automotive lubricating oil according to claim 1, characterized in that, In S2: the amount of p-methylbenzaldehyde fed is 5-10% of the mass of the primary amphiphilic polymer backbone.

6. The method for preparing a low-ash, low-sulfur automotive lubricating oil according to claim 1, characterized in that, In S3: the mass ratio of the pretreatment powder to tributyl borate is 1:2-4.

7. The method for preparing a low-ash, low-sulfur automotive lubricating oil according to claim 1, characterized in that, In S4: the mass ratio of the partially borated modified MXene powder to the fluoroalkylsilane is 1:(0.8-1.2).

8. The method for preparing a low-ash, low-sulfur automotive lubricating oil according to claim 1, characterized in that, In S5: The antioxidant is any one or a combination of two of alkylated diphenylamine and IRGANOXL135; The amount of antioxidant added is 0.1-0.5% of the mass of synthesized PAO; The defoamer is SAG47, and the amount of defoamer added is 0.01-0.05% of the mass of synthesized PAO.

9. A low-ash, low-sulfur automotive lubricating oil prepared by the preparation method according to any one of claims 1-8.

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