A binary ionic liquid lubricating additive, a preparation method and application thereof

Abstract

The application relates to a binary ionic liquid lubricating additive and a preparation method and application thereof, the binary ionic liquid lubricating additive comprising ionic liquid I and ionic liquid II with a molar ratio of 1:1, wherein the ionic liquid I comprises cation precursor I and anion precursor I with a molar ratio of 1:1, the ionic liquid II comprises cation precursor II and anion precursor II with a molar ratio of 1:1, the cation precursor I and the cation precursor II are selected from any same one of ethanolamine, dimethylethanolamine and trioctylamine, and the anion precursor I and the anion precursor II are selected from any two different ones of valeric acid, heptanoic acid and di(2-ethylhexyl) phosphate. Compared with the prior art, the application has better anti-wear effect, and can make PAO4 base oil have excellent anti-wear property.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lubricants, in particular to a binary ionic liquid lubricant additive and a preparation method and application thereof. BACKGROUND

[0002] With the growth of the world's population and the development of the economy, the demand for energy is increasing, and the problem of the limitedness of traditional energy resources is becoming increasingly prominent. In this context, energy loss is a problem that cannot be ignored. For example, in a typical passenger car, 79% of the energy generated by fuel is lost, and friction and wear are the main causes of energy loss and mechanical failure. About 1 / 3 of the world's primary energy comes from friction consumption, and nearly 1 / 2 of the power consumption of transportation equipment is consumed in friction.

[0003] Lubricating oil is one of the most effective methods to control friction and wear. Generally, lubricating oil is mainly composed of base oil and additives. Additives are an important means to improve the performance of base oil and are the essence of modern high-grade lubricating oil. The good properties of ionic liquids in tribology, such as high thermal oxidative stability, non-flammability, low volatility, and good compatibility with lubricating oil base oil, make ionic liquids one of the most ideal lubricant additives.

[0004] In recent years, with the continuous improvement of environmental protection standards, additives containing halogen or other harmful elements (such as phosphorus and sulfur) are facing environmental pressure. However, most traditional ionic liquids contain halogen. For example, the lubricant additive described in CN202210065887.7 contains three ionic liquids, and the anion contains one or more of silver trifluoromethylsulfonate, silver bis-trifluoromethanesulfonimide, silver tetrafluoroborate, and silver hexafluorophosphate. In addition, elements such as phosphorus and sulfur are still widely used in various ionic liquid lubricant additives. For example, in the ionic liquid lubricant additive described in CN202111222212.0, tetrabutylphosphonium hydroxide is used as the cation of the synthesized ionic liquid. For these additives containing phosphorus and sulfur, eliminating or reducing the content of phosphorus and sulfur has become a development trend. SUMMARY

[0005] The purpose of the present application is to overcome the defects of existing lubricant additives containing non-environmental elements and provide a binary ionic liquid lubricant additive and a preparation method and application thereof.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] One of the technical solutions of the present application is to provide a binary ionic liquid lubricant additive, which comprises ionic liquid I and ionic liquid II with a molar ratio of 1:1,

[0008] The ionic liquid I comprises cation precursor I and anion precursor I in a molar ratio of 1:1,

[0009] The ionic liquid II comprises cation precursor II and anion precursor II in a molar ratio of 1:1,

[0010] The cation precursor I and the cation precursor II are any same one selected from ethanolamine, dimethylethanolamine and trioctylamine,

[0011] The anion precursor I and the anion precursor II are any two different ones selected from valeric acid, heptanoic acid and di(2-ethylhexyl) phosphate.

[0012] The second technical solution of the present application provides a preparation method of the binary ionic liquid lubricating additive as described in any one of the above technical solutions, comprising the following steps:

[0013] S1, preparation of the ionic liquid I:

[0014] The cation precursor I and the anion precursor I are mixed, oil bath heating and stirring are performed to obtain a viscous oily liquid, and the ionic liquid I is obtained after vacuum drying;

[0015] S2, preparation of the ionic liquid II:

[0016] The cation precursor II and the anion precursor II are mixed, oil bath heating and stirring are performed to obtain a viscous oily liquid, and the ionic liquid II is obtained after vacuum drying;

[0017] S3, the ionic liquid I obtained in the step S1 is mixed with the ionic liquid II obtained in the step S2, stirring and ultrasonic treatment are performed to obtain the binary ionic liquid lubricating additive.

[0018] In some specific embodiments, in the steps S1 and S2, the temperature of oil bath heating is 30-40℃, and the time of oil bath heating is 6-8h.

[0019] In some specific embodiments, in the steps S1 and S2, the stirring speed is 760-800r / min.

[0020] In some specific embodiments, in the steps S1 and S2, the temperature of vacuum drying is 60-70℃, and the time of vacuum drying is 10-12h.

[0021] In some specific embodiments, in the step S3, the stirring speed is 750-800r / min.

[0022] In some specific embodiments, in the step S3, the time of ultrasonic treatment is 0.5-1h.

[0023] The third technical solution of the present application provides an application of the binary ionic liquid lubricating additive as described in any one of the above technical solutions, wherein the binary ionic liquid lubricating additive is used for preparing lubricating oil.

[0024] In some embodiments, the lubricating oil comprises the following components by mass fraction:

[0025] base oil 98.5-99 parts,

[0026] binary ionic liquid lubricating additive 1-1.5 parts.

[0027] In some embodiments, the base oil is PAO4.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] The present application provides a preparation method of a binary ionic liquid lubricating additive with simple steps and mild reaction conditions, which comprises the following steps: combining two ionic liquids containing the same cation and different anions in a specific ratio to prepare a binary ionic liquid lubricating additive. The binary ionic liquid lubricating oil prepared by the specific ratio has better anti-wear effect than a single ionic liquid, and can make the PAO4 base oil have excellent anti-wear property. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is an infrared spectrum of the lubricating additive of Example 1 of the present application.

[0031] Figure 2 It is an infrared spectrum of the lubricating additive of Example 2 of the present application.

[0032] Figure 3 It is an infrared spectrum of the lubricating additive of Example 3 of the present application.

[0033] Figure 4 It is a wear scar map of PAO4 base oil.

[0034] Figure 5 It is a wear scar map of the lubricating oil prepared by the lubricating additive of Example 1 of the present application.

[0035] Figure 6 It is a wear scar map of the lubricating oil prepared by the lubricating additive of Example 2 of the present application.

[0036] Figure 7 It is a wear scar map of the lubricating oil prepared by the lubricating additive of Example 3 of the present application. DETAILED DESCRIPTION

[0037] The application will be described in detail below with reference to the drawings and specific embodiments. The embodiments are implemented on the premise of the technical solutions of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following examples.

[0038] In the following examples and comparative examples, if no special description is given for raw materials or processing techniques, it is indicated that they are all conventional commercially available raw material products or conventional processing techniques in the art.

[0039] Example 1

[0040] The embodiment provides a preparation method of a valeric acid-heptanoic acid-ethanolamine binary ionic liquid lubricating additive, comprising the following steps:

[0041] (1) valeric acid-ethanolamine ionic liquid is prepared: 0.1 mol (10.21 g) of valeric acid is slowly added dropwise into 0.1 mol (6.11 g) of ethanolamine, the rotation speed of an oil bath magnetic heating stirrer is adjusted to 760 r / min, and the temperature is slowly increased to 40 DEG C, the reaction time is 6 h, after the reaction is completed, the mixture is placed in a vacuum drying box at 60 DEG C for drying for 12 h, and valeric acid-ethanolamine ionic liquid in the form of light yellow oil is obtained.

[0042] (2) heptanoic acid-ethanolamine ionic liquid is prepared: 0.1 mol (13.02 g) of heptanoic acid is slowly added dropwise into 0.1 mol (6.11 g) of ethanolamine, the rotation speed of an oil bath magnetic heating stirrer is adjusted to 760 r / min, and the temperature is slowly increased to 40 DEG C, the reaction time is 6 h, after the reaction is completed, the mixture is placed in a vacuum drying box at 60 DEG C for drying for 12 h, and heptanoic acid-ethanolamine ionic liquid in the form of light yellow oil is obtained.

[0043] (3) valeric acid-heptanoic acid-ethanolamine binary ionic liquid is prepared, and the molecular formula is shown in formula A: 0.01 mol (1.91 g) of heptanoic acid-ethanolamine ionic liquid is slowly added dropwise into 0.01 mol (1.63 g) of valeric acid-ethanolamine ionic liquid, the mixture is stirred at a rotation speed of 800 r / min at room temperature for 30 min, after the stirring is completed, ultrasonic treatment is continued for 30 min, and after the ultrasonic treatment is completed, valeric acid-heptanoic acid-ethanolamine (1:1) binary ionic liquid lubricating additive in the form of light yellow viscous substance is obtained, Figure 1 and its infrared spectrum is shown in the following figure.

[0044]

[0045] Comparative Example 1

[0046] The embodiment provides a preparation method of valeric acid-heptanoic acid-ethanolamine binary ionic liquid lubricating additive, which is same as that in the embodiment 1 except that the molar ratio of the valeric acid-ethanolamine ionic liquid to the heptanoic acid-ethanolamine ionic liquid in the binary ionic liquid lubricating additive is adjusted to 1:2 in step (3), and the specific preparation steps are as follows:

[0047] 0.02 mol (3.82 g) of the heptanoic acid-ethanolamine ionic liquid is slowly added into 0.01 mol (1.63 g) of the valeric acid-ethanolamine ionic liquid, the mixture is stirred at 800 r / min at room temperature for 30 min, and then ultrasonic treatment is further conducted for 30 min, and finally, a yellowish viscous valeric acid-heptanoic acid-ethanolamine (1:2) binary ionic liquid lubricating additive is obtained.

[0048] Comparative example 2:

[0049] The embodiment provides a preparation method of valeric acid-heptanoic acid-ethanolamine binary ionic liquid lubricating additive, which is same as that in the embodiment 1 except that the molar ratio of the valeric acid-ethanolamine ionic liquid to the heptanoic acid-ethanolamine ionic liquid in the binary ionic liquid lubricating additive is adjusted to 1:3 in step (3), and the specific preparation steps are as follows:

[0050] 0.03 mol (5.73 g) of the heptanoic acid-ethanolamine ionic liquid is slowly added into 0.01 mol (1.63 g) of the valeric acid-ethanolamine ionic liquid, the mixture is stirred at 800 r / min at room temperature for 30 min, and then ultrasonic treatment is further conducted for 30 min, and finally, a yellowish viscous valeric acid-heptanoic acid-ethanolamine (1:3) binary ionic liquid lubricating additive is obtained.

[0051] Comparative example 3:

[0052] The valeric acid-ethanolamine ionic liquid prepared in step (1) in the embodiment 1 is directly used as the lubricating additive in the comparative example.

[0053] Comparative example 4:

[0054] The heptanoic acid-ethanolamine ionic liquid prepared in step (2) in the embodiment 1 is directly used as the lubricating additive in the comparative example.

[0055] The lubricating additives in the above embodiment 1 and comparative examples 1-4 are each prepared into a lubricating oil for performance detection, and the preparation method of the lubricating oil comprises the following steps:

[0056] 0.2 g of the lubricating additive is directly added into 19.8 g of PAO4 base oil, ultrasonic treatment is conducted for 30 min, so that the additive is uniformly dispersed, and finally, a sample of the ionic liquid-containing lubricating oil containing 1 wt% is obtained, and the performance comparison results are shown in Table 1.

[0057] Performance of the lubricating oil prepared in Example 1 and Comparative Examples 1-4

[0058]

[0059] As can be seen from Table 1, the anti-wear performance of the lubricating oil prepared by adding the binary ionic liquid lubricating additive with a ratio of valeric acid anion to heptanoic acid anion of 1:1 is significantly improved compared to the lubricating oil prepared by adding the binary ionic liquid lubricating additive with different ratios of anions, and the average wear scar diameter is the smallest, which is 0.384 mm, and the average wear scar diameter is reduced by 32.63% compared to the PAO4 base oil without additive (0.570 mm), and the anti-wear performance of PAO4 is the most obvious.

[0060] Figure 4 The wear scar of the base lubricating oil PAO4, Figure 5 The wear scar of the lubricating oil prepared by the binary ionic liquid lubricating additive of Example 1.

[0061] Example 2:

[0062] The present embodiment provides a preparation method of valeric acid-heptanoic acid-dimethylethanolamine ionic liquid lubricating additive, comprising the following steps:

[0063] (1) Preparation of valeric acid-dimethylethanolamine ionic liquid: slowly add 0.1 mol (10.21 g) of valeric acid to 0.1 mol (8.91 g) of dimethylethanolamine, adjust the rotation speed of the oil bath magnetic heating stirrer to 760 r / min and slowly heat to 40°C, the reaction time is 6h, after the reaction is completed, the mixture is placed in a 60°C vacuum drying oven for drying for 12h, to obtain a light yellow oil of valeric acid-dimethylethanolamine ionic liquid.

[0064] (2) Preparation of heptanoic acid-dimethylethanolamine ionic liquid: slowly add 0.1 mol (13.02 g) of heptanoic acid to 0.1 mol (8.91 g) of dimethylethanolamine, adjust the rotation speed of the oil bath magnetic heating stirrer to 760 r / min and slowly heat to 40°C, the reaction time is 6h, after the reaction is completed, the mixture is placed in a 60°C vacuum drying oven for drying for 12h, to obtain a light yellow oil of heptanoic acid-dimethylethanolamine ionic liquid.

[0065] (3) Preparation of valeric acid-heptanoic acid-dimethylethanolamine binary ionic liquid, the molecular formula is shown as formula B: 0.01 mol (1.91 g) of valeric acid-dimethylethanolamine ionic liquid was slowly added dropwise with 0.01 mol (2.19 g) of heptanoic acid-dimethylethanolamine ionic liquid, the mixture was stirred at 800 r / min for 30 min at room temperature, and then ultrasonic treatment was continued for 30 min after completion of stirring, and a yellowish viscous valeric acid-heptanoic acid-dimethylethanolamine (1:1) binary ionic liquid lubricating additive was obtained after ultrasonic treatment was completed. Figure 2 The infrared spectrum thereof is shown in Figure 1.

[0066]

[0067] Comparative Example 5:

[0068] The present example provides a preparation method of valeric acid-heptanoic acid-dimethylethanolamine binary ionic liquid lubricating additive, which is substantially the same as that of Example 4, except that in step (3), the molar ratio of valeric acid-dimethylethanolamine ionic liquid to heptanoic acid-dimethylethanolamine ionic liquid in the binary ionic liquid lubricating additive is adjusted to 1:2, and the specific preparation steps are as follows:

[0069] 0.02 mol (4.38 g) of heptanoic acid-dimethylethanolamine ionic liquid was slowly added dropwise into 0.01 mol (1.91 g) of valeric acid-dimethylethanolamine ionic liquid, the mixture was stirred at 800 r / min for 30 min at room temperature, and then ultrasonic treatment was continued for 30 min after completion of stirring, and a yellowish viscous valeric acid-heptanoic acid-dimethylethanolamine (1:2) binary ionic liquid lubricating additive was obtained after ultrasonic treatment was completed.

[0070] Comparative Example 6:

[0071] The present example provides a preparation method of valeric acid-heptanoic acid-dimethylethanolamine binary ionic liquid lubricating additive, which is substantially the same as that of Example 4, except that in step (3), the molar ratio of valeric acid-dimethylethanolamine ionic liquid to heptanoic acid-dimethylethanolamine ionic liquid in the binary ionic liquid lubricating additive is adjusted to 1:3, and the specific preparation steps are as follows:

[0072] 0.03 mol (6.57 g) of heptanoic acid-dimethylethanolamine ionic liquid was slowly added dropwise into 0.01 mol (1.91 g) of valeric acid-dimethylethanolamine ionic liquid, the mixture was stirred at 800 r / min for 30 min at room temperature, and then ultrasonic treatment was continued for 30 min after completion of stirring, and a yellowish viscous valeric acid-heptanoic acid-dimethylethanolamine (1:3) binary ionic liquid lubricating additive was obtained after ultrasonic treatment was completed.

[0073] Comparative Example 7:

[0074] The comparative example directly uses the pentanoic acid-dimethyl ethanolamine ionic liquid prepared in step (1) of Example 4 as the lubricating additive.

[0075] Comparative Example 8:

[0076] The comparative example directly uses the heptanoic acid-dimethyl ethanolamine ionic liquid prepared in step (2) of Example 4 as the lubricating additive.

[0077] The lubricating additives in the above Example 2 and Comparative Examples 5-8 are each prepared into a lubricating oil for performance testing, and the preparation method of the lubricating oil includes the following steps:

[0078] 0.2 g of the lubricating additive is directly added into 19.8 g of PAO4 base oil, and ultrasonic treatment is performed for 30 min to uniformly disperse the additive, to obtain a lubricating oil sample containing 1 wt% of the ionic liquid, and the performance comparison results are shown in Table 2.

[0079] Table 2 Performance of the lubricating oils prepared from Example 2 and Comparative Examples 5-8

[0080]

[0081] As can be seen from Table 2, the effect achieved by adding the pentanoic acid-heptanoic acid-ethanolamine binary ionic liquid lubricating additive is consistent, and the wear scar diameter is the smallest when the pentanoic acid-heptanoic acid-dimethyl ethanolamine lubricating additive is added, and the ratio of the pentanoic acid anion to the heptanoic acid anion is 1:1, which is 0.360 mm. Compared with the PAO4 base oil without additive (0.570 mm), the average wear scar diameter is reduced by 36.84%, and the effect of improving the anti-wear performance of PAO4 is the most obvious. Compared with Table 1, the effect achieved by the lubricating additive prepared by using dimethyl ethanolamine as the cation precursor is better than that achieved by the lubricating additive prepared by using ethanolamine as the cation precursor.

[0082] Figure 4 The wear scar diameter of the base lubricating oil PAO4 tested, Figure 6 The wear scar diameter of the lubricating oil prepared from the binary ionic liquid lubricating additive of Example 2 tested.

[0083] Example 3:

[0084] The present example provides a preparation method of a di(2-ethylhexyl) phosphate-heptanoic acid-trioctylamine ionic liquid lubricating additive, which includes the following steps:

[0085] (1) Preparation of di(2-ethylhexyl) phosphate-trioctylamine ionic liquid: 0.05 mol (17.68 g) of trioctylamine was slowly added dropwise with 0.05 mol (16.12 g) of di(2-ethylhexyl) phosphate, the stirring speed of the oil bath magnetic heating stirrer was adjusted to 760 r / min and slowly heated to 40°C, the reaction time was 6 h, after the reaction was completed, the mixture was placed in a vacuum drying oven at 60°C for 12 h, and di(2-ethylhexyl) phosphate-trioctylamine ionic liquid in the form of light yellow oil was obtained.

[0086] (2) Preparation of heptanoic acid-trioctylamine ionic liquid: 0.05 mol (17.68 g) of trioctylamine was slowly added dropwise with 0.05 mol (6.51 g) of heptanoic acid, the stirring speed of the oil bath magnetic heating stirrer was adjusted to 760 r / min and slowly heated to 40°C, the reaction time was 6 h, after the reaction was completed, the mixture was placed in a vacuum drying oven at 60°C for 12 h, and heptanoic acid-trioctylamine ionic liquid in the form of light yellow oil was obtained.

[0087] (3) Preparation of di(2-ethylhexyl) phosphate-heptanoic acid-trioctylamine binary ionic liquid, the molecular formula is shown in formula C: 0.01 mol (6.76 g) of di(2-ethylhexyl) phosphate-trioctylamine ionic liquid was slowly added dropwise with 0.01 mol (4.84 g) of heptanoic acid-trioctylamine ionic liquid, the mixture was stirred at 800 r / min at room temperature for 30 min, after stirring was completed, ultrasonic was continued for 30 min, and after ultrasonic was completed, di(2-ethylhexyl) phosphate-heptanoic acid-trioctylamine (1:1) binary ionic liquid lubricating additive in the form of light yellow viscous substance was obtained, Figure 3 and its infrared spectrum is shown in Figure 2.

[0088]

[0089] Comparative Example 9:

[0090] The present example provides a preparation method of di(2-ethylhexyl) phosphate-heptanoic acid-trioctylamine binary ionic liquid lubricating additive, most of which is the same as that of Example 7, the difference lies in that in step (3), the molar ratio of di(2-ethylhexyl) phosphate-trioctylamine ionic liquid to heptanoic acid-trioctylamine ionic liquid in the binary ionic liquid lubricating additive is 1:2, and the specific preparation steps are as follows:

[0091] 0.01 mol (6.76 g) of di(2-ethylhexyl) phosphate-trioctylamine ionic liquid was slowly added dropwise with 0.02 mol (9.68 g) of heptanoic acid-trioctylamine ionic liquid, the mixture was stirred at 800 r / min at room temperature for 30 min, after stirring was completed, ultrasonic was continued for 30 min, and after ultrasonic was completed, di(2-ethylhexyl) phosphate-heptanoic acid-trioctylamine (1:2) binary ionic liquid lubricating additive in the form of light yellow viscous substance was obtained.

[0092] Comparative Example 10:

[0093] The present example provides a method for preparing a di(2-ethylhexyl) phosphate-heptanoic acid-trioctylamine binary ionic liquid lubricating additive. Most of the steps are the same as those in Example 7, except that in step (3), the molar ratio of di(2-ethylhexyl) phosphate-trioctylamine ionic liquid to heptanoic acid-trioctylamine ionic liquid in the binary ionic liquid lubricating additive is adjusted to 1:3. The specific preparation steps are as follows:

[0094] Slowly drop 0.03 mol (14.52 g) of heptanoic acid-trioctylamine ionic liquid into 0.01 mol (6.76 g) of di(2-ethylhexyl) phosphate-trioctylamine ionic liquid, and stir the mixture at 800 r / min at room temperature for 30 min. After stirring is completed, continue to ultrasonic for 30 min. After ultrasonic is completed, a light yellow viscous di(2-ethylhexyl) phosphate-heptanoic acid-trioctylamine (1:3) binary ionic liquid lubricating additive is obtained.

[0095] Comparative Example 11:

[0096] The present comparative example directly uses the di(2-ethylhexyl) phosphate-trioctylamine ionic liquid prepared in step (1) of Example 7 as a lubricating additive.

[0097] Comparative Example 12:

[0098] The present comparative example directly uses the heptanoic acid-trioctylamine ionic liquid prepared in step (2) of Example 7 as a lubricating additive.

[0099] The lubricating additives in the above Example 3 and Comparative Examples 9-12 are each prepared into a lubricating oil for performance testing. The preparation method of the lubricating oil includes the following steps:

[0100] Directly add 0.2 g of the lubricating additive into 19.8 g of PAO4 base oil, and ultrasonic for 30 min to make the additive uniformly dispersed, to obtain a 1 wt% ionic liquid-containing lubricating oil sample. The performance comparison results are shown in Table 3.

[0101] Table 3 Performance of the lubricating oils prepared from Example 3 and Comparative Examples 9-12

[0102]

[0103] As can be seen from Table 3, the addition of the di(2-ethylhexyl) phosphate-heptanoic acid-trioctylamine ionic liquid lubricating additive, and the di(2-ethylhexyl) phosphate anion and heptanoic acid anion ratio is 1:1, the minimum wear scar diameter is 0.304 mm, compared with the PAO4 base oil without additive (0.570 mm), the average wear scar diameter is reduced by 46.67%, the anti-wear performance of PAO4 is most obvious, and compared with Tables 1 and 2, the di(2-ethylhexyl) phosphate-heptanoic acid-trioctylamine lubricating oil additive achieves better effect than other binary ionic lubricating additives.

[0104] Figure 4 The wear scar of the base lubricating oil PAO4 tested, Figure 7 The wear scar of the lubricating oil tested for the binary ionic liquid lubricating additive of Example 3.

[0105] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. Those skilled in the art can obviously make various modifications to these embodiments, and apply the general principles described herein to other embodiments without having to go through creative labor. Therefore, the present application is not limited to the above embodiments, and improvements and modifications made by those skilled in the art according to the disclosure of the present application without departing from the scope of the present application should be within the scope of protection of the present application.

Claims

1. A lubricating oil, characterized in that, The components include the following parts by mass: Base oil 98.5-99 parts, 1-1.5 parts of binary ionic liquid lubricant additive, The binary ionic liquid lubricant additive comprises ionic liquid I and ionic liquid II in a molar ratio of 1:

1. Ionic liquid I comprises a cation precursor I and an anion precursor I in a molar ratio of 1:

1. Ionic liquid II comprises a cation precursor II and an anion precursor II in a molar ratio of 1:

1. The cationic precursor I and cationic precursor II are selected from any one of ethanolamine, dimethylethanolamine, and trioctylamine. When the cationic precursor I is ethanolamine, the anionic precursor I and the anionic precursor II are valeric acid and heptanoic acid, respectively. When the cationic precursor I is dimethylethanolamine, the anionic precursor I and the anionic precursor II are valeric acid and heptanoic acid, respectively. When the cationic precursor I is trioctylamine, the anionic precursor I and the anionic precursor II are heptanoic acid and di(2-ethylhexyl) phosphate, respectively.

2. The lubricating oil according to claim 1, characterized in that, The base oil is PAO4.

3. A method for preparing a lubricating oil as described in any one of claims 1 or 2, characterized in that, The preparation method of the binary ionic liquid lubricating additive includes the following steps: S1, Preparation of ionic liquid I: The cationic precursor I and the anionic precursor I were mixed, heated in an oil bath and stirred to obtain a viscous oily liquid, which was then dried under vacuum to obtain ionic liquid I. Preparation of S2 and ionic liquid II: The cationic precursor II and the anionic precursor II were mixed, heated in an oil bath and stirred to obtain a viscous oily liquid, which was then dried under vacuum to obtain ionic liquid II. S3. Mix, stir, and sonicate the ionic liquid I obtained in step S1 with the ionic liquid II obtained in step S2 to obtain a binary ionic liquid lubricant additive.

4. The preparation method according to claim 3, characterized in that, In steps S1 and S2, the oil bath heating temperature is 30-40℃, and the oil bath heating time is 6-8 h.

5. The preparation method according to claim 3, characterized in that, In steps S1 and S2, the stirring speed is 760-800 r / min.

6. The preparation method according to claim 3, characterized in that, In steps S1 and S2, the vacuum drying temperature is 60-70℃ and the vacuum drying time is 10-12 h.

7. The preparation method according to claim 3, characterized in that, In step S3, the stirring speed is 750-800 r / min.

8. The preparation method according to claim 3, characterized in that, In step S3, the ultrasound time is 0.5-1 h.

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