Antioxidant lubricating oil composition and preparation method thereof

Abstract

The invention relates to an antioxidant lubricating oil composition and a preparation method thereof, and belongs to the technical field of lubricating oil. The composition is prepared from the following components in percentage by weight: 3.8 to 4.4 percent of an extreme pressure anti-wear agent, 2.5 to 3.0 percent of a clearing agent, 2.2 to 2.8 percent of an oily additive, 0.75 to 0.92 percent of a modified antioxidant, 1.7 to 2.1 percent of an ashless dispersant, 0.4 to 0.5 percent of an anti-rust agent, 3.5 to 4.2 percent of a viscosity index improver and the balance of polyol ester base oil, the modified antioxidant is a compound with a three-branch naphthylamine structure and a central quaternary ammonium structure formed by click addition of triallylamine and 4-chlorobenzyl mercaptan, quaternization of iodoethane and substitution of 2-naphthylamine, the modified antioxidant has good antioxidant capacity at high temperature, and meanwhile, the oil sludge amount of the lubricating oil at high temperature is effectively reduced.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil technology, specifically relating to an antioxidant lubricating oil composition and its preparation method. Background Technology

[0002] Lubricating oil is the "blood" of modern industrial equipment, requiring it to maintain lubricity, heat dissipation, and corrosion resistance under high-temperature, high-speed, and heavy-load conditions. Polyol ester base oils (such as pentaerythritol esters) have become the preferred base oils for high-end equipment such as aero engines and precision instruments due to their excellent viscosity-temperature properties, high flash point, and biodegradability. Although the absence of hydrogen atoms on the β-carbon of polyol ester molecules gives them superior thermal stability compared to mineral oils, the ester groups can still undergo free radical chain oxidation under the catalytic action of high-temperature oxygen and residual metal ions from friction, generating carboxylic acids, ketones, and polymers, leading to a surge in viscosity, increased acid value, and sludge deposition.

[0003] Existing technologies mainly delay oxidation by adding antioxidants, such as common hindered phenols, diphenylamines, and naphthylamines. However, these have the following limitations: hindered phenols have high low-temperature antioxidant efficiency, but they are prone to volatilization and deactivation at high temperatures, resulting in insufficient high-temperature stability and durability; diphenylamines have better high-temperature antioxidant properties than phenols, but their linear molecular structure makes them prone to oxidation to form quinone intermediates, which crosslink with polar products of the base oil to form a gel; in contrast, naphthylamines, with their naphthalene ring conjugated system, provide excellent high-temperature free radical scavenging capabilities and are widely used in high-temperature lubricants. However, the quinone imine intermediates generated by their oxidation are prone to π-π stacking polymerization to form polycyclic aromatic hydrocarbon gels due to their strong polarity and planar rigid structure, causing filter clogging and wear. Currently, the sludge problem of naphthylamine antioxidants is mainly alleviated through two methods: compound dispersants, which coat polar sludge precursors, but cannot block the formation of quinones, and excessive addition reduces antioxidant efficiency; alkylation modification, which introduces tert-butyl groups into the naphthalene ring to delay oxidation, but the steric hindrance effect is limited, and there is still a risk of cross-linking at high temperatures, so the effect on reducing sludge formation is limited. Therefore, it is urgent to develop a lubricating oil system that has both high-temperature antioxidant and anti-sludge properties. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background art, the purpose of this invention is to provide an antioxidant lubricating oil composition and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions: An antioxidant lubricating oil composition, specifically comprising: 3.8-4.4 wt% extreme pressure anti-wear agent, 2.5-3.0 wt% detergent, 2.2-2.8 wt% oiliness additive, 0.75-0.92 wt% modified antioxidant, 1.7-2.1 wt% ashless dispersant, 0.4-0.5 wt% rust inhibitor, and 3.5-4.2 wt% viscosity index improver, with the balance being polyol ester base oil.

[0006] The modified antioxidant is prepared by the following method: Step A1: Mix triallylamine, 4-chlorobenzyl mercaptan, and acetonitrile, purge with nitrogen to remove oxygen, then add benzophenone. Irradiate at room temperature using a 365nm light source, controlling the irradiation intensity to be 40-50mW / cm². 2 The reaction was stirred for 8-11 hours. After the reaction was completed, acetonitrile was removed by rotary evaporation. The substrate was washed with n-hexane and dried under vacuum to obtain a branched intermediate. In step A1, the ratio of triallylamine, 4-chlorobenzyl mercaptan, benzophenone and acetonitrile is 0.1 mol: 0.3 mol: 1.5-2 g: 300-350 mL. Under ultraviolet light initiation, 4-chlorobenzyl mercaptan and triallylamine undergo an addition reaction.

[0007] Step A2: Mix the branched intermediate, iodoethane and anhydrous toluene, purge with dry nitrogen, add potassium carbonate, heat to 70-75℃ and stir under reflux for 4.5-6 hours. After the reaction is complete, filter to remove salts, remove toluene by rotary evaporation under reduced pressure to obtain the quaternized matrix. In step A2, the ratio of the branched intermediate, iodoethane, potassium carbonate and anhydrous toluene is 0.1 mol: 0.18-0.22 mol: 15-20 g: 400-500 mL, and the iodoethane reacts with the branched intermediate in a quaternization reaction.

[0008] Step A3: Mix the branched intermediate, 2-naphthylamine and dimethylformamide, purge with nitrogen for protection, heat to 100-120℃, slowly add triethylamine and stir for 6-8 hours. After the reaction is completed and cooled, add deionized water to wash, filter and dry the precipitate to obtain the modified antioxidant. In step A3, the ratio of the branched intermediate, 2-naphthylamine, triethylamine, and dimethylformamide is 0.1 mol: 0.31-0.32 mol: 35-45 mL: 320-380 mL, and the 2-naphthylamine is substituted with the chlorine group of the branched intermediate.

[0009] Preferably, the extreme pressure anti-wear agent is a sulfurized isobutylene preparation, which has both high extreme pressure activity and thermal stability, and is highly compatible with the high-temperature anti-oxidation conditions of lubricating oil.

[0010] Preferably, the ashless dispersant is a boron-modified succinimide formulation, which has good thermal stability, promotes dispersion in high-temperature lubrication systems, and inhibits sludge deposition.

[0011] Preferably, the viscosity index improver is a combination of ethylene propylene copolymer formulations and polymethyl methacrylate formulations, which can effectively adjust the viscosity index of lubricating oil and at the same time have good solubility and dispersibility for sludge.

[0012] A method for preparing an antioxidant lubricating oil composition includes: heating a polyol ester base oil to reduce its viscosity, sequentially adding an extreme pressure anti-wear agent, a detergent, an ashless dispersant, and a rust inhibitor and stirring to mix, cooling to 50°C, then adding an oiliness additive and a modified antioxidant and mixing, and finally adding the modified antioxidant and mixing thoroughly to obtain the antioxidant lubricating oil composition.

[0013] The beneficial effects of this invention are: This invention leverages the superior high-temperature antioxidant properties of the naphthylamine structure to formulate a modified antioxidant in polyol ester-based lubricating oils. The modified antioxidant is produced by a click addition reaction of triallylamine and 4-chlorobenzyl thiol under mild conditions, initiated by photoinitiation, to form a branched intermediate. This intermediate is then quaternized with iodoethane to form a quaternized matrix. Finally, the quaternized matrix is ​​replaced by 2-naphthylamine to form a compound with a tribranched naphthylamine structure and a central quaternary ammonium structure, thus constituting the modified antioxidant. Compared to existing technologies, in terms of antioxidant function, the rigid branched framework constructed by the click reaction of triallylamine and thiol fixes the three naphthylamine groups in... In three-dimensional space, numerous three-dimensional shielding units are formed in the composition, expanding the active hydrogen supply cross section, effectively capturing and terminating free radical reactions. At the same time, the branched sulfide structure and the central quaternary ammonium structure interact with metal ions, blocking the metal catalytic oxidation pathway and reducing oxidation. In terms of anti-sludge function, the modified antioxidant has a relatively large branched spatial structure, which hinders the contact of quinone intermediates formed after oxidation. Meanwhile, the central quaternary ammonium structure has good high-temperature stability and continuously provides electrostatic repulsion, further hindering the formation of intermediates, inhibiting π-π stacking crosslinking, reducing the formation of insoluble polymer gels, and thus reducing sludge generation. Detailed Implementation

[0014] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0015] Example 1: Preparation of an antioxidant lubricating oil composition, the specific implementation process is as follows: (1) Preparation of modified antioxidants Step A1: Mix triallylamine, 4-chlorobenzyl mercaptan, and acetonitrile, and purge with nitrogen until a stable gas flow escapes to remove oxygen. Then add benzophenone and mix well. Irradiate at room temperature using a 365nm light source, controlling the irradiation intensity to be 50mW / cm². 2The mixture was stirred for 8 hours, with the ratio of triallylamine, 4-chlorobenzyl mercaptan, benzophenone and acetonitrile being 0.1 mol: 0.3 mol: 2 g: 350 mL. After the reaction was completed, the acetonitrile was removed by rotary evaporation, the substrate was washed with n-hexane, and dried under vacuum to obtain a branched intermediate.

[0016] Step A2: Mix the branched intermediate, iodoethane, and anhydrous toluene, purge with dry nitrogen for protection, then add potassium carbonate and mix. Heat to 75°C and reflux for 4.5 h with stirring. The ratio of the branched intermediate, iodoethane, potassium carbonate, and anhydrous toluene is 0.1 mol: 0.22 mol: 20 g: 500 mL. After the reaction is complete, filter to remove salts, and remove toluene by rotary evaporation under reduced pressure to obtain the quaternized matrix.

[0017] Step A3: Mix the branched intermediate, 2-naphthylamine, and dimethylformamide, purge with nitrogen for protection, heat to 120°C, slowly add triethylamine and stir for 6 hours. The ratio of the branched intermediate, 2-naphthylamine, triethylamine, and dimethylformamide is 0.1 mol: 0.32 mol: 45 mL: 380 mL. After the reaction is complete and cooled, add deionized water to wash, filter, and dry the precipitate to obtain the modified antioxidant.

[0018] (2) Preparation of lubricating oil composition The raw materials were prepared according to the following weight percentage composition: extreme pressure anti-wear agent 4.4 wt%, a commercially available sulfurized isobutylene preparation, specifically model T321; detergent 2.7 wt%, a commercially available high-alkalinity sulfurized alkylphenol calcium preparation, specifically model T122; oiliness additive 2.5 wt%, a commercially available sulfurized olefin cottonseed oil preparation, specifically model T405A; modified antioxidant 0.75 wt%, prepared in-house in this embodiment; ashless dispersant 1.7 wt%, a commercially available boron-modified succinimide preparation, specifically model T154B; rust inhibitor 0.4 wt%, a commercially available naphthalene sulfonate preparation, specifically model T705; viscosity index improver 3.5 wt%, a combination of ethylene propylene copolymer preparation and polymethyl methacrylate preparation, specifically T614 and T602 in a weight ratio of 2:1; the balance was polyol ester base oil, specifically pentaerythritol mixed ester base oil, specifically model NP451.

[0019] The viscosity of the polyol ester base oil is reduced by heating it to 85°C. Extreme pressure anti-wear agent, detergent, ashless dispersant and rust inhibitor are added in sequence and stirred. Then the temperature is reduced to 50°C, and oily additive and modified antioxidant are added and mixed. Finally, modified antioxidant is added and mixed evenly to obtain an antioxidant lubricating oil composition.

[0020] Example 2: Preparation of an antioxidant lubricating oil composition, the specific implementation process is as follows: (1) Preparation of modified antioxidants Step A1: Mix triallylamine, 4-chlorobenzyl mercaptan, and acetonitrile, and purge with nitrogen until a stable gas flow escapes to remove oxygen. Then add benzophenone and mix well. Irradiate at room temperature using a 365nm light source, controlling the irradiation intensity to 40mW / cm². 2 The mixture was stirred for 11 hours, with the ratio of triallylamine, 4-chlorobenzyl mercaptan, benzophenone and acetonitrile being 0.1 mol: 0.3 mol: 1.5 g: 300 mL. After the reaction was completed, the acetonitrile was removed by rotary evaporation, the substrate was washed with n-hexane, and dried under vacuum to obtain a branched intermediate.

[0021] Step A2: Mix the branched intermediate, iodoethane, and anhydrous toluene, purge with dry nitrogen, add potassium carbonate, and mix. Heat to 70°C and reflux for 6 hours. The ratio of the branched intermediate, iodoethane, potassium carbonate, and anhydrous toluene is 0.1 mol: 0.18 mol: 15 g: 400 mL. After the reaction is complete, filter to remove salts, and remove toluene by rotary evaporation under reduced pressure to obtain the quaternized matrix.

[0022] Step A3: Mix the branched intermediate, 2-naphthylamine and dimethylformamide, purge with nitrogen for protection, heat to 100℃, slowly add triethylamine and stir for 8 hours. The ratio of the branched intermediate, 2-naphthylamine, triethylamine and dimethylformamide is 0.1mol:0.31mol:35mL:320mL. After the reaction is complete and cooled, add deionized water to wash, filter and dry the precipitate to obtain the modified antioxidant.

[0023] (2) Preparation of lubricating oil composition The raw materials were prepared according to the following weight percentage composition: extreme pressure anti-wear agent 3.8 wt%, a commercially available sulfurized isobutylene preparation, specifically model T321; detergent 3.0 wt%, a commercially available high-alkalinity sulfurized alkylphenol calcium preparation, specifically model T122; oiliness additive 2.2 wt%, a commercially available sulfurized olefin cottonseed oil preparation, specifically model T405A; modified antioxidant 0.92 wt%, prepared in-house in this embodiment; ashless dispersant 2.1 wt%, a commercially available boron-modified succinimide preparation, specifically model T154B; rust inhibitor 0.5 wt%, a commercially available naphthalene sulfonate preparation, specifically model T705; viscosity index improver 4.2 wt%, a combination of ethylene propylene copolymer preparation and polymethyl methacrylate preparation, specifically T614 and T602 in a weight ratio of 2:1; the balance was polyol ester base oil, specifically pentaerythritol mixed ester base oil, specifically model NP451.

[0024] The viscosity of the polyol ester base oil is reduced by heating it to 85°C. Extreme pressure anti-wear agent, detergent, ashless dispersant and rust inhibitor are added in sequence and stirred. Then the temperature is reduced to 50°C, and oily additive and modified antioxidant are added and mixed. Finally, modified antioxidant is added and mixed evenly to obtain an antioxidant lubricating oil composition.

[0025] Example 3: Preparation of an antioxidant lubricating oil composition, the specific implementation process is as follows: (1) Preparation of modified antioxidants Step A1: Mix triallylamine, 4-chlorobenzyl mercaptan, and acetonitrile, and purge with nitrogen until a stable gas flow escapes to remove oxygen. Then add benzophenone and mix well. Irradiate at room temperature using a 365nm light source, controlling the irradiation intensity to 45mW / cm². 2 The mixture was stirred for 10 h, with the ratio of triallylamine, 4-chlorobenzyl mercaptan, benzophenone and acetonitrile being 0.1 mol: 0.3 mol: 1.8 g: 320 mL. After the reaction was completed, the acetonitrile was removed by rotary evaporation, the substrate was washed with n-hexane, and dried under vacuum to obtain a branched intermediate.

[0026] Step A2: Mix the branched intermediate, iodoethane, and anhydrous toluene, purge with dry nitrogen, add potassium carbonate, and mix. Heat to 70°C and reflux for 5.5 h with stirring. The ratio of the branched intermediate, iodoethane, potassium carbonate, and anhydrous toluene is 0.1 mol: 0.2 mol: 17 g: 450 mL. After the reaction is complete, filter to remove salts, and remove toluene by rotary evaporation under reduced pressure to obtain the quaternized matrix.

[0027] Step A3: Mix the branched intermediate, 2-naphthylamine, and dimethylformamide, purge with nitrogen for protection, heat to 110℃, slowly add triethylamine and stir for 7 hours. The ratio of the branched intermediate, 2-naphthylamine, triethylamine, and dimethylformamide is 0.1 mol: 0.31 mol: 40 mL: 350 mL. After the reaction is complete and cooled, add deionized water to wash, filter, and dry the precipitate to obtain the modified antioxidant.

[0028] (2) Preparation of lubricating oil composition The raw materials were prepared according to the following weight percentage composition: extreme pressure anti-wear agent 4.2 wt%, a commercially available sulfurized isobutylene preparation, specifically model T321; detergent 2.5 wt%, a commercially available high-alkalinity sulfurized alkylphenol calcium preparation, specifically model T122; oiliness additive 2.8 wt%, a commercially available sulfurized olefin cottonseed oil preparation, specifically model T405A; modified antioxidant 0.85 wt%, prepared in-house in this embodiment; ashless dispersant 1.9 wt%, a commercially available boron-modified succinimide preparation, specifically model T154B; rust inhibitor 0.42 wt%, a commercially available naphthalene sulfonate preparation, specifically model T705; viscosity index improver 3.8 wt%, a compound of ethylene propylene copolymer preparation and polymethyl methacrylate preparation, specifically T614 and T602 in a weight ratio of 2:1; the balance is polyol ester base oil, specifically pentaerythritol mixed ester base oil, specifically model NP451.

[0029] The viscosity of the polyol ester base oil is reduced by heating it to 85°C. Extreme pressure anti-wear agent, detergent, ashless dispersant and rust inhibitor are added in sequence and stirred. Then the temperature is reduced to 50°C, and oily additive and modified antioxidant are added and mixed. Finally, modified antioxidant is added and mixed evenly to obtain an antioxidant lubricating oil composition.

[0030] Example 4: Preparation of an antioxidant lubricating oil composition, the specific implementation process is as follows: (1) Preparation of modified antioxidants Step A1: Mix triallylamine, 4-chlorobenzyl mercaptan, and acetonitrile, and purge with nitrogen until a stable gas flow escapes to remove oxygen. Then add benzophenone and mix well. Irradiate at room temperature using a 365nm light source, controlling the irradiation intensity to 45mW / cm². 2 The mixture was stirred for 9 hours, with the ratio of triallylamine, 4-chlorobenzyl mercaptan, benzophenone and acetonitrile being 0.1 mol: 0.3 mol: 2 g: 320 mL. After the reaction was completed, the acetonitrile was removed by rotary evaporation, the substrate was washed with n-hexane, and dried under vacuum to obtain a branched intermediate.

[0031] Step A2: Mix the branched intermediate, iodoethane, and anhydrous toluene, purge with dry nitrogen for protection, then add potassium carbonate and mix. Heat to 72°C and reflux for 5.2 h with stirring. The ratio of the branched intermediate, iodoethane, potassium carbonate, and anhydrous toluene is 0.1 mol: 0.19 mol: 17 g: 440 mL. After the reaction is complete, filter to remove salts, and remove toluene by rotary evaporation under reduced pressure to obtain the quaternized matrix.

[0032] Step A3: Mix the branched intermediate, 2-naphthylamine, and dimethylformamide, purge with nitrogen for protection, heat to 110℃, slowly add triethylamine and stir for 6.5 h. The ratio of the branched intermediate, 2-naphthylamine, triethylamine, and dimethylformamide is 0.1 mol: 0.32 mol: 42 mL: 340 mL. After the reaction is complete and cooled, add deionized water to wash, filter, and dry the precipitate to obtain the modified antioxidant.

[0033] (2) Preparation of lubricating oil composition The raw materials were prepared according to the following weight percentage composition: extreme pressure anti-wear agent 4.1 wt%, a commercially available sulfurized isobutylene preparation, specifically model T321; detergent 2.8 wt%, a commercially available high-alkalinity sulfurized alkylphenol calcium preparation, specifically model T122; oiliness additive 2.6 wt%, a commercially available sulfurized olefin cottonseed oil preparation, specifically model T405A; modified antioxidant 0.88 wt%, prepared in-house in this embodiment; ashless dispersant 2 wt%, a commercially available boron-modified succinimide preparation, specifically model T154B; rust inhibitor 0.45 wt%, a commercially available naphthalene sulfonate preparation, specifically model T705; viscosity index improver 4.1 wt%, a combination of ethylene propylene copolymer and polymethyl methacrylate preparations, specifically T614 and T602 in a weight ratio of 2:1; the balance being polyol ester base oil, specifically pentaerythritol mixed ester base oil, specifically model NP451.

[0034] The viscosity of the polyol ester base oil is reduced by heating it to 85°C. Extreme pressure anti-wear agent, detergent, ashless dispersant and rust inhibitor are added in sequence and stirred. Then the temperature is reduced to 50°C, and oily additive and modified antioxidant are added and mixed. Finally, modified antioxidant is added and mixed evenly to obtain an antioxidant lubricating oil composition.

[0035] In the comparative example, referring to Example 4, the modified antioxidant was replaced in equal amounts with a low-sludge alkylated naphthylamine antioxidant, specifically model L06, and the rest of the implementation process was exactly the same.

[0036] Samples were taken from the lubricating oil composition prepared above. Oxidation resistance was tested using the rotating oxygen bomb method according to ASTM D2272-22; sludge content was tested using the heat pipe deposition method according to ASTM D4310-20; and a four-ball wear test was conducted at 120°C and 392N according to ASTM D4172-21. Specific test results are shown in Table 1. Table 1 As can be seen from the comparison of test data in Table 1, the oxidation induction time of the lubricating oils prepared in the examples all reached more than 300 min. Combined with the test data, the oxidation induction time is slightly higher than that of the comparative example, indicating excellent high-temperature oxidation resistance. At the same time, in the high-temperature four-ball wear test, the wear condition is slightly better than that of the comparative example, possibly due to less oxidation and more sufficient lubrication. In the heat pipe deposition test, the amount of grease produced by the lubricating oils in the examples is significantly lower than that in the comparative example, effectively solving the defect of existing naphthylamine antioxidants that are prone to producing sludge.

[0037] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0038] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. An antioxidant lubricating oil composition, characterized in that, The specific components are: extreme pressure anti-wear agent 3.8-4.4 wt%, detergent 2.5-3.0 wt%, oiliness additive 2.2-2.8 wt%, modified antioxidant 0.75-0.92 wt%, ashless dispersant 1.7-2.1 wt%, rust inhibitor 0.4-0.5 wt%, and viscosity index improver 3.5-4.2 wt%, with the balance being polyol ester base oil; The modified antioxidant is prepared by the following method: Step A1: Mix triallylamine, 4-chlorobenzyl mercaptan, and acetonitrile, purge with nitrogen to remove oxygen, then add benzophenone at room temperature at 40-50 mW / cm³. 2 The reaction was stirred under ultraviolet light for 8-11 hours to prepare a branched intermediate. Step A2: Mix the branched intermediate, iodoethane and anhydrous toluene, purge with dry nitrogen, add potassium carbonate, heat to 70-75℃ and stir under reflux for 4.5-6 hours to prepare the quaternized matrix; Step A3: Mix the branched intermediate, 2-naphthylamine and dimethylformamide, purge with nitrogen, heat to 100-120℃, slowly add triethylamine and stir for 6-8 hours to prepare the modified antioxidant.

2. The antioxidant lubricating oil composition according to claim 1, characterized in that, The ratio of triallylamine, 4-chlorobenzyl mercaptan, benzophenone, and acetonitrile is 0.1 mol: 0.3 mol: 1.5-2 g: 300-350 mL.

3. The antioxidant lubricating oil composition according to claim 2, characterized in that, The ratio of branched intermediate, iodoethane, potassium carbonate and anhydrous toluene is 0.1 mol: 0.18-0.22 mol: 15-20 g: 400-500 mL.

4. The antioxidant lubricating oil composition according to claim 3, characterized in that, The ratio of branched intermediate, 2-naphthylamine, triethylamine and dimethylformamide is 0.1 mol: 0.31-0.32 mol: 35-45 mL: 320-380 mL.

5. The antioxidant lubricating oil composition according to claim 1, characterized in that, The extreme pressure anti-wear agent is a sulfurized isobutylene preparation.

6. The antioxidant lubricating oil composition according to claim 1, characterized in that, The ashless dispersant is a boron-modified succinimide formulation.

7. The antioxidant lubricating oil composition according to claim 1, characterized in that, Viscosity index improvers are formulated by combining ethylene propylene copolymer formulations and polymethyl methacrylate formulations.

8. A method for preparing an antioxidant lubricating oil composition according to any one of claims 1-7, characterized in that, Specifically, the polyol ester base oil is heated to reduce viscosity, and extreme pressure anti-wear agent, detergent, ashless dispersant and rust inhibitor are added in sequence and stirred. The mixture is then cooled to 50°C, and oily additives and modified antioxidants are added and mixed. Finally, modified antioxidants are added and mixed thoroughly to obtain an antioxidant lubricating oil composition.

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