Chelated lithium-molybdenum-iron ion lubricating oil additive and preparation method thereof

Abstract

The invention discloses a chelated lithium-molybdenum-iron ion lubricating oil additive and a preparation method thereof, and relates to the technical field of lubricating oil, the additive is prepared from the following components by weight: 80-100 parts of an ionic liquid, 0.5-1.5 parts of an antifoaming agent, 0.5-3 parts of an antioxidant, and 0.5-2 parts of an emulsifier; the prepared additive has good dispersity in base oil, can endow lubricating oil with excellent lubricating properties such as high bearing capacity, low friction coefficient and high wear resistance, effectively makes up and improves the performance defects of the base oil, and is wide in application range and simple to prepare.

Description

Technical Field

[0001] The invention relates to the technical field of lubricating oils, and in particular to a chelated lithium-molybdenum-iron ion lubricating oil additive and a preparation method thereof. Background Art

[0002] Energy is essential for our sustainable future, and overcoming friction consumes a lot of energy, especially in the transportation, industry and power generation sectors. The wear and tear of products and components and their replacement will cause significant economic and energy losses. According to statistics, about 100 million megajoules are used to overcome friction every year in the world, which is one-fifth of the energy generated. The largest energy users are industry (29%) and transportation (27%). According to recent studies on energy use, it is estimated that by effectively implementing new tribological solutions, 133 billion liters of fuel can be saved each year in the short term (5 to 9 years) and carbon dioxide emissions can be effectively reduced. China's energy consumption per unit of GDP is higher than the world average, and the losses caused by friction and wear reach hundreds of millions of yuan each year, which will also seriously affect the reliability and accuracy of machine parts. Minimizing mechanical wear is a global challenge in addressing environmental issues.

[0003] Ionic liquid lubricant additives are a new type of lubricant additives with unique properties and application prospects. This type of additive has many excellent characteristics: good thermal stability, can remain stable at high temperatures; low vapor pressure, small volatility loss; excellent lubrication performance and friction reduction effect; good compatibility with a variety of base oils and additives; environmentally friendly, good biodegradability. Its mechanism of action mainly includes the formation of protective film, nano effect and ternary reaction. An ordered adsorption film is formed on the friction surface to reduce friction and wear; some ionic liquids can form nanostructures, fill microscopic bumps and improve surface quality; react with metal surfaces to form tribochemical reaction films, further improving wear resistance.

[0004] Ionic liquid lubricant additives have a wide range of applications, including high-temperature lubrication (such as aircraft engines, high-speed bearings, etc.), extreme conditions (vacuum, high pressure, low temperature and other special environments), micro-nano lubrication (MEMS, precision instruments, etc.) and metal processing (cutting, forming and other processes). Compared with traditional additives, it has the advantages of excellent performance, versatility and designability.

[0005] Chinese patent document CN116638096A discloses a method for preparing water-soluble nano copper and its application as a water-based lubricant additive in combination with proton-type ionic liquid. The invention uses an in-situ surface modification method to rapidly and on a large scale prepare copper nanoparticles anchored by anionic groups, and then uses a thiol-containing surfactant to modify the anionic groups, and the thiol-containing water-soluble organic compound is modified on the surface of the metallic copper to form a stable organic single-molecule surface-modified nano copper particle. At the same time, the obtained water-soluble copper nanoparticles are compounded with proton-type ionic liquids, which can be dispersed stably in a water-alcohol system for a long time without oxidation, and the system has extremely high extreme pressure anti-wear lubrication performance, which is manifested as a low friction coefficient and a maximum non-seizure PB value of up to 3090N.

[0006] However, this new type of additive also faces some challenges, such as high cost, compatibility with certain materials needs to be improved, and long-term stability and environmental impact need to be further improved. Summary of the invention

[0007] In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide a chelated lithium molybdenum iron ion lubricant additive and a preparation method thereof. The prepared additive has good dispersibility in the base oil and can give the lubricant oil excellent lubricating properties such as high load-bearing capacity, low friction coefficient, and high wear resistance, effectively compensating for and improving the performance defects of the base oil.

[0008] In order to achieve the above object, the present invention adopts the following technical solution:

[0009] The present invention claims a chelated lithium molybdenum iron ion lubricant additive, which is made of the following components in parts by weight: 80 to 100 parts of ionic liquid, 0.5 to 1.5 parts of defoaming agent, 0.5 to 3 parts of antioxidant, and 0.5 to 2 parts of emulsifier.

[0010] Preferably, the composition is made of the following components by weight: 90 parts of ionic liquid, 1 part of defoaming agent, 2 parts of antioxidant, and 1.5 parts of emulsifier.

[0011] Preferably, the solute in the ionic liquid is chelated lithium molybdenum ion or chelated lithium iron ion, and the chemical formula of the chelated lithium molybdenum ion is Li 2 C 10 H 16 N 2 O 8 Mo, the chemical formula of the chelated lithium iron ion is Li 2 C 10 H 16 N 2 O 8 Fe, the concentration of chelated lithium molybdenum ions is 0.1-1wt%, and the concentration of chelated lithium iron ions is 0.1-1wt%.

[0012] Specifically, the concentration of the chelated lithium molybdenum ion can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, or 1wt%; the concentration of the chelated lithium iron ion can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, or 1wt%.

[0013] Preferably, the preparation method of the chelated lithium molybdenum ion solution is as follows: weigh EDTA and dissolve it in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; weigh lithium salt and molybdenum salt at a molar ratio of EDTA:Li:Mo of 1:1-2:0.5-1, add them to the EDTA solution, stir and react at 40-80°C for 1-3h to obtain chelated lithium molybdenum ions.

[0014] Specifically, the lithium salt is lithium acetate, and the molybdenum salt is molybdenum nitrate.

[0015] Preferably, the preparation method of the chelated lithium iron ion solution is as follows: weigh EDTA and dissolve it in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; weigh lithium salt and iron salt at a molar ratio of EDTA:Li:Fe of 1:1-2:0.5-1 and add them to the EDTA solution, stir and react at 40-80°C for 1-3h to obtain chelated lithium iron ions.

[0016] Specifically, the lithium salt is lithium acetate, and the iron salt is ferric nitrate.

[0017] Preferably, the defoaming agent is one or more of tributyl phosphate, polyether modified silicone oil, and methyl silicone oil.

[0018] Preferably, the antioxidant is one or more of zinc dialkyl dithiophosphate, distearyl thiodipropionate, dodecyl selenium, 2,6-di-tert-butyl-p-cresol, and zinc dialkyl dithiocarbamate.

[0019] Preferably, the emulsifier is one or more of lignin sulfonate, carboxymethyl cellulose, diglycerol polypropylene glycol ether, oleic acid polyoxyethylene ester, and fatty amide polyoxyethylene ether.

[0020] Preferably, the additive is added to the lubricating oil in an amount of 0.1 to 2 wt%.

[0021] Specifically, the additive may be added to the lubricating oil in an amount of 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, or 2wt%.

[0022] The present invention also claims protection for a method for preparing the chelated lithium molybdenum iron ion lubricant additive, comprising the following steps: adding an emulsifier to the ionic liquid, ultrasonically dispersing it evenly, then adding a defoaming agent and an antioxidant, stirring the reaction, centrifuging, washing, and drying the product to obtain the chelated lithium molybdenum iron ion lubricant additive.

[0023] Preferably, the ultrasonic time is 10 to 30 min, and the stirring reaction conditions are 30 to 40° C. and 4 to 8 h.

[0024] Specifically, the ultrasonic time can be 10 min, 15 min, 20 min, 25 min, 30 min; the stirring reaction temperature can be 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C; the stirring reaction time can be 4h, 5h, 6h, 7h, 8h.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1) The present invention provides a chelated lithium molybdenum iron ion lubricant additive, which can form a protective film on the friction surface by introducing chelated lithium molybdenum ions and chelated lithium iron ions into the lubricant, effectively reducing the friction coefficient and improving the lubrication effect. At the same time, these chelated metal ions can react chemically with the friction surface to form a wear-resistant protective layer to enhance the wear resistance of parts. The added special antioxidant component can delay the oxidation aging of the lubricant and extend its service life, while the addition of the defoaming agent inhibits the generation of foam during the use of the lubricant and ensures the lubrication effect. The use of an emulsifier improves the dispersion stability of the additive in the lubricant and prevents stratification and precipitation. In addition, the additive formula is suitable for various types of base lubricants and has a wide range of applications. Its preparation process adopts ultrasonic dispersion and stirring reaction, which is simple and easy to operate and convenient for large-scale production. With ionic liquid as the main carrier, it is more environmentally friendly than traditional additives. By adjusting the proportion of each component, the performance of the additive can be optimized for different application scenarios. These effects combined significantly improve the comprehensive performance and service life of the lubricant, which is of great significance to improving the operating efficiency and life of mechanical equipment.

[0027] 2) The present invention provides an ionic liquid. The two chelated metal ions, chelated lithium molybdenum ions and chelated lithium iron ions, can form a strong protective film on the friction surface, significantly improving the lubrication performance. They can form a thin and stable tribochemical reaction film on the metal surface through chemical adsorption and reaction. This film has good compression and shear resistance and can effectively reduce the friction coefficient and wear rate. In particular, the chelated lithium molybdenum ions can form MoS under high temperature and high pressure conditions. 2 The film has excellent anti-wear and extreme pressure properties, which can significantly improve the load-bearing capacity of lubricants under harsh working conditions. At the same time, the chelated lithium iron ions can form Fe 3 O 4 The chelated lithium molybdenum ions and chelated lithium iron ions form an oxide protective layer, further enhancing the wear resistance of the surface. The synergistic effect of the two chelated ions not only improves the lubrication effect, but also enhances the antioxidant properties. They can capture free radicals and inhibit the oxidation process of the lubricant, thereby extending the service life of the lubricant. In addition, due to the use of EDTA as a chelating agent, the formed chelate has good thermal and chemical stability and can remain active under various temperature and pH conditions. The introduction of chelated lithium molybdenum ions and chelated lithium iron ions also improves the dispersibility and stability of additives in lubricants. They can form a stable colloidal system with the lubricant base oil, prevent the precipitation and stratification of additives, and ensure the performance stability during long-term use. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0029] Unless otherwise specified, the chemical reagents and materials in the present invention are purchased from commercial sources or synthesized from raw materials purchased from commercial sources.

[0030] A method for preparing a chelated lithium molybdenum iron ion lubricating oil additive comprises the following steps:

[0031] (1) Weighing EDTA and dissolving it in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; weighing lithium salt and molybdenum salt in a molar ratio of EDTA:Li:Mo of 1:1-2:0.5-1, adding them to the EDTA solution, stirring and reacting at 40-80° C. for 1-3 hours to obtain chelated lithium molybdenum ions;

[0032] (2) Weighing EDTA and dissolving it in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; weighing lithium salt and iron salt in a molar ratio of EDTA:Li:Fe of 1:1-2:0.5-1, adding them to the EDTA solution, stirring and reacting at 40-80° C. for 1-3 hours to obtain chelated lithium iron ions;

[0033] (3) diluting the chelated lithium molybdenum ions and the chelated lithium iron ions with EDTA to obtain an ionic liquid, wherein the concentration of the chelated lithium molybdenum ions is 0.1 to 1 wt %, and the concentration of the chelated lithium iron ions is 0.1 to 1 wt %;

[0034] (4) Add 0.5 to 2 parts of emulsifier to 80 to 100 parts of ionic liquid, ultrasonically disperse for 10 to 30 minutes, then add 0.5 to 1.5 parts of defoamer and 0.5 to 3 parts of antioxidant, stir and react at 30 to 40° C. for 4 to 8 hours, centrifuge, wash and dry the product to obtain the chelated lithium molybdenum iron ion lubricating oil additive.

[0035] The defoaming agent is one or more of tributyl phosphate, polyether modified silicone oil, and methyl silicone oil; the antioxidant is one or more of dialkyl zinc dithiophosphate, distearyl thiodipropionate, dodecyl selenium, 2,6-di-tert-butyl-p-cresol, and dialkyl zinc dithiocarbamate; the emulsifier is one or more of lignin sulfonate, methyl cellulose, diglycerol polypropylene glycol ether, oleic acid polyoxyethylene ester, and fatty amide polyoxyethylene ether.

[0036] The additive is added in an amount of 0.1 to 2 wt % in the lubricating oil.

[0037] The present invention will be further described below through specific embodiments.

[0038] Example 1

[0039] A method for preparing a chelated lithium molybdenum iron ion lubricating oil additive comprises the following steps:

[0040] (1) EDTA is weighed and dissolved in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; lithium acetate and molybdenum nitrate are weighed and added to the EDTA solution at a molar ratio of EDTA:Li:Mo of 1:2:1, and the mixture is stirred and reacted at 80° C. for 1 h to obtain chelated lithium molybdenum ions;

[0041] (2) Weighing EDTA and dissolving it in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; weighing lithium acetate and ferric nitrate at a molar ratio of EDTA:Li:Fe of 1:2:1 and adding them to the EDTA solution, stirring and reacting at 80°C for 1 hour to obtain chelated lithium iron ions;

[0042] (3) diluting the chelated lithium molybdenum ions and the chelated lithium iron ions with EDTA to obtain an ionic liquid, wherein the concentration of the chelated lithium molybdenum ions is 1wt%, and the concentration of the chelated lithium iron ions is 1wt%;

[0043] (4) 1.5 g of emulsifier carboxymethyl cellulose is added to 100 g of ionic liquid, and ultrasonically dispersed for 20 min. Then, 1 g of defoamer polyether-modified silicone oil and 2 g of antioxidant 2,6-di-tert-butyl-p-cresol are added. The reaction is stirred at 35 ° C. for 6 h. The product is centrifuged, washed, and dried to obtain the chelated lithium molybdenum iron ion lubricating oil additive.

[0044] The additive is added in an amount of 1.2 wt % in the lubricating oil.

[0045] Example 2

[0046] A method for preparing a chelated lithium molybdenum iron ion lubricating oil additive comprises the following steps:

[0047] (1) EDTA is weighed and dissolved in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; lithium acetate and molybdenum nitrate are weighed and added to the EDTA solution at a molar ratio of EDTA:Li:Mo of 1:1.8:0.9, and the mixture is stirred and reacted at 70° C. for 2 h to obtain chelated lithium molybdenum ions;

[0048] (2) Weighing EDTA and dissolving it in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; weighing lithium acetate and ferric nitrate at a molar ratio of EDTA:Li:Fe of 1:1.8:0.9 and adding them to the EDTA solution, stirring and reacting at 70°C for 2 hours to obtain chelated lithium iron ions;

[0049] (3) diluting the chelated lithium molybdenum ions and the chelated lithium iron ions with EDTA to obtain an ionic liquid, wherein the concentration of the chelated lithium molybdenum ions is 0.8wt%, and the concentration of the chelated lithium iron ions is 0.8wt%;

[0050] (4) 1.5 g of emulsifier carboxymethyl cellulose is added to 90 g of ionic liquid, and ultrasonic dispersion is performed for 20 min. Then, 1 g of defoamer polyether-modified silicone oil and 2 g of antioxidant 2,6-di-tert-butyl-p-cresol are added. The reaction is stirred at 35 ° C. for 6 h. The product is centrifuged, washed, and dried to obtain the chelated lithium molybdenum iron ion lubricating oil additive.

[0051] The additive is added in an amount of 1.2 wt % in the lubricating oil.

[0052] Example 3

[0053] A method for preparing a chelated lithium molybdenum iron ion lubricating oil additive comprises the following steps:

[0054] (1) EDTA is weighed and dissolved in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; lithium acetate and molybdenum nitrate are weighed and added to the EDTA solution at a molar ratio of EDTA:Li:Mo of 1:1.4:0.7, and the mixture is stirred and reacted at 60° C. for 2 h to obtain chelated lithium molybdenum ions;

[0055] (2) Weighing EDTA and dissolving it in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; weighing lithium acetate and ferric nitrate at a molar ratio of EDTA:Li:Fe of 1:1.4:0.7 and adding them to the EDTA solution, stirring and reacting at 60°C for 2 hours to obtain chelated lithium iron ions;

[0056] (3) diluting the chelated lithium molybdenum ions and the chelated lithium iron ions with EDTA to obtain an ionic liquid, wherein the concentration of the chelated lithium molybdenum ions is 0.4wt%, and the concentration of the chelated lithium iron ions is 0.4wt%;

[0057] (4) 1.5 g of emulsifier carboxymethyl cellulose is added to 90 g of ionic liquid, and ultrasonic dispersion is performed for 20 min. Then, 1 g of defoamer polyether-modified silicone oil and 2 g of antioxidant 2,6-di-tert-butyl-p-cresol are added. The reaction is stirred at 35 ° C. for 6 h. The product is centrifuged, washed, and dried to obtain the chelated lithium molybdenum iron ion lubricating oil additive.

[0058] The additive is added in an amount of 0.8 wt % in the lubricating oil.

[0059] Example 4

[0060] A method for preparing a chelated lithium molybdenum iron ion lubricating oil additive comprises the following steps:

[0061] (1) EDTA is weighed and dissolved in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; lithium acetate and molybdenum nitrate are weighed and added to the EDTA solution at a molar ratio of EDTA:Li:Mo of 1:1:0.5, and the mixture is stirred and reacted at 40° C. for 3 h to obtain chelated lithium molybdenum ions;

[0062] (2) Weighing EDTA and dissolving it in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; weighing lithium acetate and ferric nitrate at a molar ratio of EDTA:Li:Fe of 1:1:0.5 and adding them to the EDTA solution, stirring and reacting at 40°C for 3 hours to obtain chelated lithium iron ions;

[0063] (3) diluting the chelated lithium molybdenum ions and the chelated lithium iron ions with EDTA to obtain an ionic liquid, wherein the concentration of the chelated lithium molybdenum ions is 0.1wt%, and the concentration of the chelated lithium iron ions is 0.1wt%;

[0064] (4) 1.5 g of emulsifier carboxymethyl cellulose is added to 80 g of ionic liquid, and ultrasonic dispersion is performed for 20 min. Then, 1 g of defoamer polyether-modified silicone oil and 2 g of antioxidant 2,6-di-tert-butyl-p-cresol are added, and the reaction is stirred at 35 ° C for 6 h. The product is centrifuged, washed, and dried to obtain the chelated lithium molybdenum iron ion lubricating oil additive.

[0065] The additive is added in an amount of 1 wt % in the lubricating oil.

[0066] Comparative Example 1

[0067] A method for preparing a lubricating oil additive comprises the following steps:

[0068] (1) EDTA is weighed and dissolved in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; lithium acetate and molybdenum nitrate are weighed and added to the EDTA solution at a molar ratio of EDTA:Li:Mo of 1:2:1, and the mixture is stirred and reacted at 80° C. for 1 h to obtain chelated lithium molybdenum ions;

[0069] (2) diluting the chelated lithium platinum ions with EDTA to obtain an ionic liquid, wherein the concentration of the chelated lithium platinum ions is 1 wt %;

[0070] (3) 1.5 g of emulsifier carboxymethyl cellulose is added to 100 g of ionic liquid, and ultrasonic dispersion is performed for 20 min. Then, 1 g of defoamer polyether-modified silicone oil and 2 g of antioxidant 2,6-di-tert-butyl-p-cresol are added, and the mixture is stirred and reacted at 35° C. for 6 h. The product is centrifuged, washed, and dried to obtain the lubricating oil additive.

[0071] The additive is added in an amount of 1.2 wt % in the lubricating oil.

[0072] Comparative Example 2

[0073] A method for preparing a lubricating oil additive comprises the following steps:

[0074] (1) Weighing EDTA and dissolving it in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; weighing lithium acetate and iron nitrate at a molar ratio of EDTA:Li:Fe of 1:2:1 and adding them to the EDTA solution, stirring and reacting at 80°C for 1 hour to obtain chelated lithium iron ions;

[0075] (2) diluting the chelated lithium iron ions with EDTA to obtain an ionic liquid, wherein the concentration of the chelated lithium iron ions is 1 wt %;

[0076] (3) 1.5 g of emulsifier carboxymethyl cellulose is added to 100 g of ionic liquid, and ultrasonic dispersion is performed for 20 min. Then, 1 g of defoamer polyether-modified silicone oil and 2 g of antioxidant 2,6-di-tert-butyl-p-cresol are added, and the mixture is stirred and reacted at 35° C. for 6 h. The product is centrifuged, washed, and dried to obtain the lubricating oil additive.

[0077] The additive is added in an amount of 1.2 wt % in the lubricating oil.

[0078] Comparative Example 3

[0079] A method for preparing a lubricating oil additive comprises the following steps:

[0080] 1.5 g of emulsifier carboxymethyl cellulose was added to 100 g of EDTA, and ultrasonic dispersion was performed for 20 min. Then, 1 g of defoamer polyether-modified silicone oil and 2 g of antioxidant 2,6-di-tert-butyl-p-cresol were added, and the mixture was stirred and reacted at 35° C. for 6 h. The product was centrifuged, washed, and dried to obtain the lubricating oil additive.

[0081] The additive is added in an amount of 1.2 wt % in the lubricating oil.

[0082] The additives prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were added to 500SN base oil, and after ultrasonic mixing, the maximum no-seizure load (P) was tested by using a MS-10A four-ball friction tester produced by Xiamen Tianji Automation Co., Ltd., using a grade II bearing steel ball (diameter 12.7 mm, material GCrl5, hardness HRC 64-66) that meets the standard of GB / T 308.1-2013 "Rolling bearing balls Part 1: Steel balls", and referring to GB / T 3142-2019 "Determination of the load-bearing capacity of lubricants - Four-ball method" B ), friction spot diameter, friction coefficient, specific data see Table 1.

[0083] Table 1 Lubricant additive performance test results

[0084] <![CDATA[P B (N)]]> Friction spot diameter (mm) Friction coefficient Example 1 0.724 0.208 0.076 Example 2 713 0.211 0.081 Example 3 705 0.213 0.087 Example 4 692 0.225 0.092 Comparative Example 1 631 0.293 0.143 Comparative Example 2 619 0.312 0.168 Comparative Example 3 587 0.354 0.254

[0085] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A chelated lithium molybdenum iron ion lubricating oil additive, characterized in that: The invention is prepared from the following components by weight: 80 to 100 parts of ionic liquid, 0.5 to 1.5 parts of defoaming agent, 0.5 to 3 parts of antioxidant and 0.5 to 2 parts of emulsifier.

2. The chelated lithium molybdenum iron ion lubricating oil additive according to claim 1, characterized in that: The solute in the ionic liquid is chelated lithium molybdenum ion and chelated lithium iron ion, and the chemical formula of the chelated lithium molybdenum ion is Li2C 10 H 16 N2O8Mo, the chemical formula of the chelated lithium iron ion is Li2C 10 H 16 N2O8Fe, the concentration of chelated lithium molybdenum ions is 0.1-1wt%, and the concentration of chelated lithium iron ions is 0.1-1wt%.

3. The chelated lithium molybdenum iron ion lubricating oil additive according to claim 2, characterized in that: The preparation method of the chelated lithium molybdenum ion is as follows: weigh EDTA and dissolve it in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; weigh lithium salt and molybdenum salt at a molar ratio of EDTA:Li:Mo of 1:1-2:0.5-1, add them to the EDTA solution, stir and react at 40-80° C. for 1-3 hours to obtain the chelated lithium molybdenum ion.

4. The chelated lithium molybdenum iron ion lubricating oil additive according to claim 2, characterized in that: The preparation method of the chelated lithium iron ion is as follows: weigh EDTA and dissolve it in dilute ammonia water to form an EDTA solution with a concentration of 1 mol / L; weigh lithium salt and iron salt at a molar ratio of EDTA:Li:Fe of 1:1-2:0.5-1, add them to the EDTA solution, stir and react at 40-80°C for 1-3h to obtain chelated lithium iron ions.

5. The chelated lithium molybdenum iron ion lubricating oil additive according to claim 1, characterized in that: The defoaming agent is one or more of tributyl phosphate, polyether modified silicone oil and methyl silicone oil.

6. The chelated lithium molybdenum iron ion lubricating oil additive according to claim 1, characterized in that: The antioxidant is one or more of zinc dialkyl dithiophosphate, distearyl thiodipropionate, dodecyl selenium, 2,6-di-tert-butyl-p-cresol, and zinc dialkyl dithiocarbamate.

7. The chelated lithium molybdenum iron ion lubricating oil additive according to claim 1, characterized in that: The emulsifier is one or more of lignin sulfonate, carboxymethyl cellulose, diglycerol polypropylene glycol ether, oleic acid polyoxyethylene ester, and fatty amide polyoxyethylene ether.

8. The chelated lithium molybdenum iron ion lubricating oil additive according to claim 1, characterized in that: The additive is added in an amount of 0.1 to 2 wt % in the lubricating oil.

9. A method for preparing the chelated lithium molybdenum iron ion lubricating oil additive according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: adding an emulsifier into an ionic liquid, uniformly dispersing the liquid by ultrasonication, then adding a defoamer and an antioxidant, stirring the liquid for reaction, centrifuging, washing and drying the product to obtain the chelated lithium molybdenum iron ion lubricating oil additive.

10. The preparation method according to claim 9, characterized in that: The ultrasonic time is 10 to 30 minutes, and the stirring reaction conditions are 30 to 40° C. and 4 to 8 hours.