Gas engine lubricating oil and method for its production

Abstract

The application belongs to the technical field of lubricating oil, and specifically provides a gas engine lubricating oil and a preparation method thereof.The gas engine lubricating oil comprises the following raw materials: ester base oil, anti-wear agent, dispersant, pour point depressant and antifoaming agent, wherein the ester base oil is prepared by esterification reaction of polyhydric alcohol and fatty acid; the preparation method of the anti-wear agent comprises the following steps: first, reacting acrylic acid with vinyl imidazole to prepare a modifier; then, polymeric phenol is obtained by polymerization of phenol under the action of a catalyst; finally, the polymeric phenol, boric acid and vegetable oil are reacted, the modifier is added after a certain time of reaction, and the reaction is continued to obtain the anti-wear agent.The preparation method of the gas engine lubricating oil of the application is that the raw material components are uniformly mixed according to the formula, and the gas engine lubricating oil of the application has good wear resistance, oxidation resistance, high-temperature detergency and thermal stability.

Description

Technical Field

[0001] This application belongs to the field of lubricating oil technology, and in particular relates to a gas engine lubricating oil and its preparation method. Background Technology

[0002] Gas turbine engines are internal combustion engines powered by gaseous fuels such as natural gas, coal gas, and biogas. They differ significantly from traditional gasoline and diesel engines in their working principles and operating conditions. First, gas turbine engines have higher combustion chamber temperatures, which accelerate fuel oxidation. Second, gas turbine engines are more difficult to lubricate. Traditional liquid fuels are injected into the cylinder as small droplets, which lubricate and cool the intake and exhaust valves and valve seats. However, gaseous fuels enter the cylinder as gases, which do not provide lubrication and easily cause wear on these components.

[0003] To improve oxidation and lubrication issues, antioxidants and ash-dependent anti-wear agents are typically added to lubricating oils. Patent application CN119799394A discloses a natural gas engine lubricating oil, its preparation method, and its application. The natural gas engine lubricating oil includes detergents, dispersants, antioxidants, pour point depressants, antifoaming agents, and base oils. The antioxidants include ZDDP, amine antioxidants, and aminothioester antioxidants. This natural gas engine lubricating oil exhibits good high-temperature detergency, oxidation resistance, dispersibility, and anti-wear properties through the synergistic effect of different types of antioxidants.

[0004] However, gas engines are sensitive to ash content. Excessive ash will deposit in the valve system, which may clog the lubrication channels and aggravate wear. Insufficient ash content makes it difficult to form an effective lubrication film and achieve good lubrication effect. Summary of the Invention

[0005] To address the aforementioned problems and further improve the lubrication performance of gas engine lubricating oil, this application provides a gas engine lubricating oil and its preparation method.

[0006] This application first provides a gas engine lubricating oil, comprising the following components in parts by weight: 80-90 parts of ester base oil, 5-10 parts of anti-wear agent, 0.5-5 parts of dispersant, 0-0.5 parts of pour point depressant, and 0.1-0.5 parts of antifoaming agent; wherein the ester base oil is prepared by reacting polyols with fatty acids;

[0007] The anti-wear agent is prepared by the following steps:

[0008] S1: A modifier is prepared by reacting acrylic acid with vinylimidazole;

[0009] S2: Phenol polymerizes under the action of a catalyst to obtain phenol polymer;

[0010] S3: React phenol polymer, boric acid, and vegetable oil, add a modifier, and react further. After the reaction, remove the distillate.

[0011] Furthermore, in step S1, vinylimidazole is one of 1-vinylimidazole, 1-vinyl-3-hexadecylimidazole bromide, or 1-vinyl-3-ethylimidazole bromide.

[0012] Furthermore, in step S1, the molar ratio of acrylic acid to vinylimidazole is 1:(1-1.2).

[0013] Furthermore, in step S2, the phenol is one or more of phenol, p-methoxyphenol, hydroquinone, and p-tert-butylcatechol.

[0014] Furthermore, in step S3, the vegetable oil is one or more of soybean oil, castor oil, and tung oil.

[0015] Furthermore, in step S3, the mass ratio of phenolic polymer, boric acid, vegetable oil, and modifier is 100:(5-15):(5-20):(10-20).

[0016] Furthermore, the dispersant is one or more of monosuccinimide, bissuccinimide, and high molecular weight succinimide.

[0017] Furthermore, the pour point depressant is polymethyl methacrylate.

[0018] Furthermore, the antifoaming agent is a silicone-based or non-silicone-based antifoaming agent.

[0019] This application also provides a method for preparing a gas engine lubricating oil, comprising the following steps: weighing ester base oil, anti-wear agent, dispersant, pour point depressant, and antifoaming agent according to the formula and mixing them evenly.

[0020] Compared with the prior art, this application has the following beneficial effects:

[0021] 1. This application introduces boron atoms into the anti-wear agent to improve its thermal stability.

[0022] 2. The polyacrylic acid and alkyl imidazole in the anti-wear agent of this application can form a strong adsorption layer with the friction metal surface at high temperature, adsorb at the friction interface, form a high-strength oil film, effectively isolate direct contact with the metal surface, reduce wear, and inhibit the formation of carbon deposits and sludge, thus maintaining the high-temperature cleanliness of the engine.

[0023] 3. The anti-wear agent of this application has good compatibility with the base oil, high bonding strength, and good antioxidant properties. Attached Figure Description

[0024] Figure 1 The thermogravimetric curves of the anti-wear agents in Examples 1-2 and Control Groups 2-3 of this application are shown. Detailed Implementation

[0025] To make the inventive objectives, technical solutions, and beneficial technical effects of this application clearer, the following detailed description is provided in conjunction with embodiments, clearly and completely describing the technical solutions in the embodiments of this application. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] Unless otherwise defined, 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 belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0027] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only,” “consisting of,” etc., is used, in which case another component may be added.

[0028] The terms "preferred," "more preferably," "better," and "even better" used in this application refer to embodiments of this application that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this application. That is, in this application, "preferred," "more preferably," "better," and "even better" are merely descriptions of implementations or embodiments with better effects, but do not constitute a limitation on the scope of protection of this application.

[0029] In this application, terms such as "further," "even more," and "particularly" are used for descriptive purposes and to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0030] In this application, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0031] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0032] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0033] In this application, "above" or "below" includes the number itself. For example, "below 1" includes 1.

[0034] In this application, room temperature refers to 0-40°C, including but not limited to 10-40°C, or further to 20-30°C.

[0035] Based on extensive experimental research, this application provides a gas engine lubricating oil comprising the following components in parts by weight: 80-90 parts of ester base oil, 5-10 parts of anti-wear agent, 0.5-5 parts of dispersant, 0-0.5 parts of pour point depressant, and 0.1-0.5 parts of anti-foaming agent; wherein the ester base oil is prepared by reacting polyols with fatty acids;

[0036] The anti-wear agent is prepared by the following steps:

[0037] S1: A modifier is prepared by reacting acrylic acid with vinylimidazole;

[0038] S2: Phenol polymerizes under the action of a catalyst to obtain phenol polymer;

[0039] S3: React phenol polymer, boric acid, and vegetable oil, add a modifier, and react further. After the reaction, remove the distillate.

[0040] In some embodiments of this application, the ester base oil comprises 80-90 parts, for example, 80 parts, 82 parts, 85 parts, 87 parts, or 90 parts; the anti-wear agent comprises 5-10 parts, for example, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts; the dispersant comprises 0.5-5 parts, for example, 0.5 parts, 1 part, 2 parts, 2.5 parts, 3 parts, 4 parts, or 5 parts; the pour point depressant comprises 0-0.5 parts, for example, 0 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, or 0.5 parts; and the antifoaming agent comprises 0.1-0.5 parts, for example, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, or 0.5 parts.

[0041] In some embodiments of this application, the addition of an anti-wear agent improves the thermal stability, oxidation resistance, friction resistance, and high-temperature detergency of the gas engine lubricating oil. This is because: Firstly, the introduction of boron into the anti-wear agent enhances thermal stability. Secondly, the phenolic hydroxyl groups can consume free radicals generated at high temperatures, which is beneficial for improving the lubricating oil's oxidation resistance at high temperatures. Thirdly, at high temperatures, the carboxyl groups and imidazole rings in the anti-wear agent can form a strong adsorption layer on the metal surface, adsorbing at the friction interface to form a high-strength oil film, effectively isolating direct contact with the metal surface and reducing wear; simultaneously, it can inhibit the formation of carbon deposits and sludge, maintaining the engine's high-temperature detergency. Furthermore, the carboxyl groups and hydroxyl groups in the anti-wear agent can react with the hydroxyl groups in the base oil, increasing the bonding strength between the anti-wear agent and the base oil, further improving the anti-wear properties, lubrication performance, and dispersibility of the anti-wear agent in the base oil, and also improving the thermal stability and oxidation resistance of the base oil. Fourthly, the addition of vegetable oil during the preparation process improves the compatibility between the anti-wear agent and the base oil, further enhancing the lubricating oil's thermal stability and lubrication performance.

[0042] In some specific embodiments of this application, in step S1, vinylimidazole is one of 1-vinylimidazole, 1-vinyl-3-hexadecylimidazole bromide, and 1-vinyl-3-ethylimidazole bromide.

[0043] In some specific embodiments of this application, in step S1, the molar ratio of acrylic acid to vinylimidazole is 1:(1-1.2), for example, it can be 1:1, 1:1.05, 1:1, 1:1.15, or 1:2.

[0044] In some embodiments of this application, in step S2, the phenol is one or more of phenol, p-methoxyphenol, hydroquinone, and p-tert-butylcatechol.

[0045] In some embodiments of this application, in step S3, the vegetable oil is one or more of soybean oil, castor oil, and tung oil. Adding vegetable oil during the preparation process improves the compatibility between the anti-wear agent and the base oil.

[0046] In some embodiments of this application, in step S3, the mass ratio of phenolic polymer, boric acid, vegetable oil, and modifier is 100:(5-15):(5-20):(10-20). For example, it can be 100:5:5:10, 100:5:10:10, 100:5:15:10, 100:5:20:10, 100:10:5:10, 100:10:10:10, 100:10:15:10, 100:10:20:10, 100:15:5:10, 100:15:10:10. 100:15:15:10, 100:15:20:10, 100:15:5:10, 100:15:10:10, 100:15:15:10, 100:15:20:10, 100:10:10:10, 100:10:10:12, 100:10:10:15, 100:10:10:18, 100:10:10:20, 100:15:20:20, 100:10:20:20, 100:5:20:20, 100:10:15:15.

[0047] In some specific embodiments of this application, the dispersant is one or more of monosuccinimide, bissuccinimide, and high molecular weight succinimide.

[0048] In some specific embodiments of this application, the pour point depressant is polymethyl methacrylate.

[0049] In some specific embodiments of this application, the antifoaming agent is a silicone-based or non-silicone-based antifoaming agent.

[0050] The second aspect of this application is to provide a method for preparing a gas engine lubricating oil, comprising the following steps: weighing ester base oil, anti-wear agent, dispersant, pour point depressant, and antifoaming agent according to the formula and mixing them evenly.

[0051] The present application will be further illustrated by the following examples, but these examples do not limit the scope of the present application.

[0052] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this application, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description in this application, any prior art methods, equipment, and materials similar to or equivalent to those described, used, or made by the methods, equipment, and materials in the embodiments of this application may be used to implement this application.

[0053] Example 1

[0054] The gas engine lubricating oil of this embodiment comprises the following components by weight: 80 parts ester base oil, 5 parts anti-wear agent, 0.5 parts monosuccinimide dispersant, 0.5 parts polymethyl methacrylate, and 0.1 parts methyl silicone oil; the preparation method of the ester base oil is as follows:

[0055] Trimethylolpropane, pentaerythritol, isooctanoic acid, and nonanoic acid were weighed into a three-necked flask with a carboxyl to hydroxyl molar ratio of 1:0.95 and a mass ratio of isooctanoic acid to nonanoic acid of 3:7. Then, potassium hydroxide (1% by mass) was added, and the esterification reaction was carried out at 200°C. The reaction was stopped when the acid value of the product was close to 0.5 mgKOH / g. The product and activated carbon were added into the flask at a mass ratio of 100:1, mixed evenly, and then distilled under reduced pressure at 220°C to obtain the product.

[0056] The anti-wear agent in this embodiment is prepared using the following steps:

[0057] S1: Weigh 7.2g of acrylic acid, add 200mL of methanol, stir and mix evenly under nitrogen protection, add 9.4g of 1-vinylimidazole and 0.16g of ammonium persulfate, react at 65℃ for 2h, after the reaction is completed, filter the reaction solution under reduced pressure, wash with methanol and dry to obtain the modifier;

[0058] S2: Weigh 4.7g of phenol, 2g of sodium dodecyl sulfate and 100mL of phosphate buffer solution with pH=7, add them to a flask, sonicate for 10min, then add 0.01g of horseradish peroxidase, stir for 10min, add 20mL of 5% hydrogen peroxide solution dropwise, continue the reaction for 1h, after the reaction is complete, add a small amount of sodium chloride solid to the reaction solution, heat to 45℃, stir until a large amount of precipitate appears, filter, wash the filter cake with distilled water and dry to obtain phenol polymer;

[0059] S3: Add 10g of phenolic polymer, 0.5g of boric acid, 0.5g of soybean oil, 20mL of toluene and 0.05g of sodium hydroxide to a three-necked flask. Heat to 100℃ under high-speed stirring and react for 5h. Reflux and remove water for 1h. Add 1g of modifier and continue reacting for 2h. Then raise the system temperature to 150℃ and remove the distillate.

[0060] The preparation method of the gas engine lubricating oil in this embodiment is as follows:

[0061] Weigh out 80 parts of ester base oil, 5 parts of anti-wear agent, 0.5 parts of monosuccinimide dispersant, 0.5 parts of polymethyl methacrylate, and 0.1 parts of methyl silicone oil according to the formula, mix and stir evenly.

[0062] Example 2

[0063] The gas engine lubricating oil of this embodiment includes the following components by weight: 90 parts ester base oil, 10 parts anti-wear agent, 5 parts bis(succinimide) dispersant, 0.5 parts polymethyl methacrylate, and 0.5 parts methyl silicone oil.

[0064] The preparation method of the ester base oil is the same as that in Example 1;

[0065] The anti-wear agent in this embodiment is prepared using the following steps:

[0066] S1: Weigh 7.2g of acrylic acid, add 200mL of methanol, stir and mix evenly under nitrogen protection, add 40g of 1-vinyl-3-hexadecylimidazolium bromide and 0.4g of ammonium persulfate, react at 65℃ for 2h, after the reaction is completed, filter the reaction solution under reduced pressure, wash with methanol and dry to obtain the modifier.

[0067] S2: Weigh 5.5g of hydroquinone, 2g of sodium dodecyl sulfate and 100mL of phosphate buffer solution with pH=7, add them to a flask, sonicate for 10min, then add 0.01g of horseradish peroxidase, stir for 10min, add 20mL of 5% hydrogen peroxide solution dropwise, continue the reaction for 1h, after the reaction is complete, add a small amount of sodium chloride solid to the reaction solution, heat to 45℃, stir until a large amount of precipitate appears, filter, wash the filter cake with distilled water and dry to obtain phenol polymer;

[0068] S3: Add 10g of phenol polymer, 1g of boric acid, 2g of castor oil, 20mL of toluene and 0.05g of sodium hydroxide to a three-necked flask. Heat to 100℃ under high-speed stirring and react for 5h. Reflux and remove water for 1h. Add 2g of modifier and continue to react for 2h. Then raise the system temperature to 150℃ and remove the distillate.

[0069] The preparation method of the gas engine lubricating oil in this embodiment is as follows:

[0070] Weigh out 90 parts of ester base oil, 10 parts of anti-wear agent, 5 parts of bis(succinimide) dispersant, 0.5 parts of polymethyl methacrylate, and 0.5 parts of methyl silicone oil according to the formula, mix and stir evenly.

[0071] Control group 1

[0072] The gas engine lubricating oil in this control group includes the following components by weight: 80 parts ester base oil, 0.5 parts monosuccinimide dispersant, 0.5 parts polymethyl methacrylate, and 0.1 parts methyl silicone oil;

[0073] The ester base oil was prepared using the same method as in Example 1;

[0074] The preparation method of the gas engine lubricating oil in this control group is as follows:

[0075] Weigh out 80 parts of ester base oil, 0.5 parts of monosuccinimide dispersant, 0.5 parts of polymethyl methacrylate, and 0.1 parts of methyl silicone oil according to the formula, mix and stir evenly.

[0076] Control group 2

[0077] The gas engine lubricating oil in this control group includes the following components by weight: 80 parts ester base oil, 5 parts anti-wear agent, 0.5 parts monosuccinimide dispersant, 0.5 parts polymethyl methacrylate, and 0.1 parts methyl silicone oil.

[0078] The ester base oil was prepared using the same method as in Example 1;

[0079] The anti-wear agent in this control group was prepared using the following steps:

[0080] S1: Weigh 4.7g of phenol, 2g of sodium dodecyl sulfate and 100mL of phosphate buffer solution with pH=7, add them to a flask, sonicate for 10min, then add 0.01g of horseradish peroxidase, stir for 10min, add 20mL of 5% hydrogen peroxide solution dropwise, continue the reaction for 1h, after the reaction is complete, add a small amount of sodium chloride solid to the reaction solution, heat to 45℃, stir until a large amount of precipitate appears, filter, wash the filter cake with distilled water and dry to obtain phenol polymer;

[0081] S2: Add 10g of phenolic polymer, 0.5g of boric acid, 0.5g of soybean oil, 20mL of toluene and 0.05g of sodium hydroxide to a three-necked flask. Heat to 100℃ under high-speed stirring and react for 5h. Reflux and remove water for 1h. Add 1g of modifier and continue reacting for 2h. Then raise the system temperature to 150℃ and remove the distillate.

[0082] The preparation method of the gas engine lubricating oil in this control group is as follows:

[0083] Weigh out 80 parts of ester base oil, 5 parts of anti-wear agent, 0.5 parts of monosuccinimide dispersant, 0.5 parts of polymethyl methacrylate, and 0.1 parts of methyl silicone oil according to the formula, mix and stir evenly.

[0084] Control group 3

[0085] The gas engine lubricating oil in this control group includes the following components by weight: 80 parts ester base oil, 5 parts anti-wear agent, 0.5 parts monosuccinimide dispersant, 0.5 parts polymethyl methacrylate, and 0.1 parts methyl silicone oil.

[0086] The ester base oil was prepared using the same method as in Example 1;

[0087] The anti-wear agent in this control group was prepared using the following steps:

[0088] Weigh 7.2g of acrylic acid, add 200mL of methanol, stir and mix evenly under nitrogen protection, add 9.4g of 1-vinylimidazole and 0.16g of ammonium persulfate, react at 65℃ for 2h. After the reaction is completed, filter the reaction solution under reduced pressure, wash with methanol and dry.

[0089] The preparation method of the gas engine lubricating oil in this control group is as follows:

[0090] Weigh out 80 parts of ester base oil, 5 parts of anti-wear agent, 0.5 parts of monosuccinimide dispersant, 0.5 parts of polymethyl methacrylate, and 0.1 parts of methyl silicone oil according to the formula, mix and stir evenly.

[0091] Performance testing

[0092] 1. High-temperature detergency: Refer to the crankcase simulation test method of SH / T 0300 to determine the coke weight. The lower the coke weight, the better the high-temperature detergency of the lubricating oil.

[0093] 2. Antioxidant properties: Refer to SH / T 0719 Lubricating oil oxidation induction period test method to determine the oxidation induction period. The longer the oxidation induction period, the better the antioxidant properties of the lubricating oil.

[0094] 3. Anti-wear properties: Refer to GB / T 3142 for the determination of the load-carrying capacity of lubricating oils. Measure the maximum non-seize load. The higher the maximum non-seize load, the better the anti-wear properties of the lubricating oil.

[0095] The test results of coke weight, oxidation induction period and maximum non-seize load of the gas engine lubricating oils of Examples 1-2 and Control Groups 1-3 are shown in Table 1 below.

[0096] Table 1 Performance of gas engine lubricating oils in Examples 1-2 and Control Groups 1-3

[0097]

[0098] As can be seen from Table 1, the gas engine lubricating oils of Examples 1-2 have good high-temperature detergency, oxidation resistance and anti-wear properties.

[0099] 4. Thermogravimetric analysis: The thermal decomposition temperature of the anti-wear agents in Examples 1-2 and Control Groups 2-3 was determined using a thermogravimetric analyzer under a nitrogen atmosphere at a heating rate of 10℃ / min. The thermogravimetric curves are shown below. Figure 1 As shown, from Figure 1 As can be seen, the gas engine lubricating oils of Examples 1-2 have higher thermal stability than the gas engine lubricating oils of Control Groups 2-3.

[0100] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A gas engine lubricating oil, characterized in that: It comprises the following components in parts by weight: 80-90 parts of ester base oil, 5-10 parts of anti-wear agent, 0.5-5 parts of dispersant, 0-0.5 parts of pour point depressant, and 0.1-0.5 parts of antifoaming agent; wherein the ester base oil is prepared by reacting polyols with fatty acids; The anti-wear agent is prepared by the following steps: S1: A modifier is prepared by reacting acrylic acid with vinylimidazole; wherein the vinylimidazole is one of 1-vinylimidazole, 1-vinyl-3-hexadecylimidazole bromide, and 1-vinyl-3-ethylimidazole bromide; S2: Phenol is polymerized under the action of a catalyst to obtain a phenol polymer; the phenol is one or more of phenol, p-methoxyphenol, hydroquinone, and p-tert-butylcatechol; S3: React phenol polymer, boric acid, and vegetable oil, add a modifier, and react further. After the reaction, remove the distillate.

2. The gas engine lubricating oil according to claim 1, characterized in that: In step S1, the molar ratio of acrylic acid to vinylimidazole is 1:(1-1.2).

3. The gas engine lubricating oil according to claim 1, characterized in that: In step S3, the vegetable oil is one or more of soybean oil, castor oil, and tung oil.

4. The gas engine lubricating oil according to claim 1, characterized in that: In step S3, the mass ratio of phenolic polymer, boric acid, vegetable oil and modifier is 100:(5-15):(5-20):(10-20).

5. The gas engine lubricating oil according to claim 1, characterized in that: The dispersant is one or more of monosuccinimide, bissuccinimide, and high molecular weight succinimide.

6. The gas engine lubricating oil according to claim 1, characterized in that: The pour point depressant is polymethyl methacrylate.

7. The gas engine lubricating oil according to claim 1, characterized in that: The antifoaming agent is either silicone-based or non-silicone-based.

8. A method for preparing a gas engine lubricating oil according to any one of claims 1-7, characterized in that: The process includes the following steps: Weigh out the ester base oil, anti-wear agent, dispersant, pour point depressant, and antifoaming agent according to the formula, and mix them evenly.

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