A functionalized urea-based gemini imidazole docusate salt and its preparation method and application

Abstract

The present invention provides a functionalized urea-based gemini imidazole docusate salt and its preparation method and application, which relate to the technical field of lubricating materials. The functionalized urea-based gemini imidazole docusate salt provided by the present invention includes a cation and an anion; the molar ratio of the cation and the anion is 1:2; the cation is a functionalized urea-based gemini imidazole, and the anion is a docusate salt. The functionalized urea-based gemini imidazole docusate salt provided by the present invention has excellent friction reduction and anti-wear properties, can be used as a lubricating factor to form a uniform and stable lubricating system in lubricating oil, and the lubricating material has good thermal stability and excellent tribological properties. At the same time, the functionalized urea-based gemini imidazole docusate salt also has excellent corrosion inhibition properties, and can be used as a corrosion inhibitor to effectively block the corrosion of acidic media on metal material substrates.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating materials, and in particular to a functionalized urea-based gemini imidazole docusate salt, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of industry, more and more mechanical equipment is operating in harsh environments such as high temperatures and extreme pressures. Every year, equipment damage caused by friction results in significant economic losses and wasted resources. In the field of lubrication, as the precision requirements of mechanical equipment continue to increase and application scenarios become more complex, the development of more efficient lubricants has become a favorable option. Lubricating oil is an effective solution to friction and wear problems. It has the advantages of low cost, long service life, and high temperature resistance. It is the most widely used of all lubricants. Improving the performance of lubricants through additives to adapt them to various extreme environments has long been a hot research topic.

[0003] Imidazole ionic liquids are common lubricant additives. They are often rich in reactive elements such as N, O, and S, which react with metals during friction to form anti-wear compounds. However, conventional imidazole ionic liquids often suffer from shortcomings such as poor solubility in base oils, hygroscopicity in air, and halogen-containing anions that can corrode metal surfaces. Summary of the Invention

[0004] The present invention aims to provide a functionalized urea-based gemini imidazole docusate salt, its preparation method, and application. The functionalized urea-based gemini imidazole docusate salt provided by the present invention has excellent friction-reducing and anti-wear properties and can be used as a lubricating factor to form a uniform and stable lubricating system in lubricating oil. The lubricating material has good thermal stability and excellent tribological properties. Furthermore, the functionalized urea-based gemini imidazole docusate salt also has excellent corrosion inhibition properties and can be used as a corrosion inhibitor to effectively prevent acidic media from corroding metal substrates.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a functionalized urea-based gemini imidazole docusate salt, comprising a cation and an anion; the molar ratio of the cation to the anion is 1:2;

[0007] The cation has a structure shown in Formula I:

[0008]

[0009] In the formula I, R is C1 to C 18 Alkyl;

[0010] The anion has a structure shown in Formula II:

[0011]

[0012] Preferably, R is methyl, ethyl, propyl, butyl, isobutyl, pentyl, isopentyl, octyl, isooctyl, decyl, isodecyl, dodecyl, tetradecyl, hexadecyl or octadecyl.

[0013] The present invention provides a method for preparing the functionalized urea-based gemini imidazole docusate salt described in the above technical solution, comprising the following steps:

[0014] mixing hexamethylene diisocyanate, 1-(3-aminopropyl)imidazole and a first organic solvent to carry out a ureidation reaction to obtain a urea-functionalized imidazole salt;

[0015] Mixing the urea-functionalized imidazole salt and an alkyl halide, and performing a quaternization reaction to obtain a urea-functionalized imidazole salt having a long alkyl chain structure;

[0016] The urea-functionalized imidazole salt having a long alkyl chain structure, sodium salt of dioctyl sulfosuccinate, and a second organic solvent are mixed to perform an ion exchange reaction to obtain the functionalized urea-functionalized gemini imidazole docusate salt;

[0017] The urea-functionalized imidazole salt has a structure shown in Formula III:

[0018]

[0019] Preferably, the molar ratio of hexamethylene diisocyanate to 1-(3-aminopropyl)imidazole is 1:2.

[0020] Preferably, the temperature of the urea formation reaction is 75-85° C., and the time is 3-5 hours.

[0021] Preferably, the molar ratio of the urea-functionalized imidazole salt to the alkyl halide is 1:2 to 2.2.

[0022] Preferably, the temperature of the quaternization reaction is 75-85° C., and the time is 8-48 hours.

[0023] Preferably, the molar ratio of the urea-functionalized imidazole salt having a long alkyl chain structure to the sodium salt of dioctyl sulfosuccinate is 1:2 to 2.2.

[0024] Preferably, the temperature of the ion exchange reaction is 75-85° C., and the time is 8-48 hours.

[0025] The present invention provides applications of the functionalized urea-based gemini imidazole docusate salt described in the above technical solution or the functionalized urea-based gemini imidazole docusate salt prepared by the preparation method described in the above technical solution in the fields of lubrication, rust prevention or corrosion inhibition.

[0026] The present invention provides a functionalized urea-based gemini imidazole docusate salt, comprising a cation and an anion in a molar ratio of 1:2; the cation is a functionalized urea-based gemini imidazole, and the anion is a docusate salt. The present invention introduces an alkyl chain and a urea functional group into the imidazole structure. The resulting functionalized urea-based gemini imidazole docusate salt has excellent oil solubility and can be used as a lubricant additive. It exhibits good thermal stability and excellent tribological properties in lubricating oils. The functionalized urea-based gemini imidazole docusate salt also has excellent corrosion inhibition properties and can be used as a corrosion inhibitor to effectively prevent corrosive media from corroding metal substrates. Specifically, the present invention introduces a long alkyl chain structure at position 2 of the imidazole ring, simultaneously enhancing the antioxidant properties of the functionalized urea-based gemini imidazole docusate salt. The introduced urea functional group can bind to the metal surface by forming a coordination bond, improving the adsorption performance of the functionalized urea-based gemini imidazole docusate salt and inhibiting corrosion. Compared to traditional hexafluorophosphates or tetrafluoroborates, the docusate group introduced into the anion of the present invention has excellent corrosion resistance and a certain degree of cleanliness (it can effectively inhibit the deposition of interfacial carbon and maintain the cleanliness of the friction pair), thereby improving corrosion resistance. At the same time, the active element S contained in the anion is also conducive to participating in tribochemical reactions and forming anti-wear compounds.

[0027] The functionalized urea-based gemini imidazole docusate salt provided by the present invention also has excellent corrosion inhibition performance and can be used as a corrosion inhibitor for metal material substrates in acidic media. Specifically, the functionalized urea-based gemini imidazole docusate salt can be effectively adsorbed on the surface of the metal material substrate, and the nitrogen atoms in the urea group form stable coordination bonds with the metal in the metal material substrate to form a dense adsorption film. In addition, the hydrophobic chains in the functionalized urea-based gemini imidazole docusate salt can extend back into the water and entangle with each other to form a dense hydrophobic film, which can effectively block the corrosion of the metal material substrate by the acidic medium, thereby playing an anti-corrosion role. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the Tafel polarization curve of 2M16-DOSS;

[0029] Figure 2 This is the salt spray test picture of 2M16-DOSS. DETAILED DESCRIPTION

[0030] The present invention provides a functionalized urea-based gemini imidazole docusate salt, comprising a cation and an anion; the molar ratio of the cation to the anion is 1:2;

[0031] The cation has a structure shown in Formula I:

[0032]

[0033] In the formula I, R is C1 to C18 Alkyl;

[0034] The anion has a structure shown in Formula II:

[0035]

[0036] In the present invention, R is methyl, ethyl, propyl, butyl, isobutyl, pentyl, isopentyl, octyl, isooctyl, decyl, isodecyl, dodecyl, tetradecyl, hexadecyl or octadecyl, more preferably dodecyl or hexadecyl.

[0037] The present invention provides a method for preparing the functionalized urea-based gemini imidazole docusate salt described in the above technical solution, comprising the following steps:

[0038] mixing hexamethylene diisocyanate, 1-(3-aminopropyl)imidazole and a first organic solvent to carry out a ureidation reaction to obtain a urea-functionalized imidazole salt;

[0039] Mixing the urea-functionalized imidazole salt and an alkyl halide, and performing a quaternization reaction to obtain a urea-functionalized imidazole salt having a long alkyl chain structure;

[0040] The urea-functionalized imidazole salt having a long alkyl chain structure, sodium salt of dioctyl sulfosuccinate, and a second organic solvent are mixed to perform an ion exchange reaction to obtain the functionalized urea-functionalized gemini imidazole docusate salt;

[0041] The urea-functionalized imidazole salt has a structure shown in Formula III:

[0042]

[0043] The present invention mixes 1,6-hexamethylene diisocyanate, 1-(3-aminopropyl)imidazole and a first organic solvent, performs a urea reaction, and obtains a urea-functionalized imidazole salt. In the present invention, the molar ratio of the 1,6-hexamethylene diisocyanate and the 1-(3-aminopropyl)imidazole is preferably 1:2. In the present invention, the first organic solvent preferably includes acetonitrile, methanol or isopropanol, more preferably acetonitrile. In the present invention, the amount ratio of the 1-(3-aminopropyl)imidazole to the first organic solvent is preferably 0.1 mol:140-160 mL.

[0044] In the present invention, mixing hexamethylene diisocyanate, 1-(3-aminopropyl)imidazole, and a first organic solvent preferably includes dropwise adding 1-(3-aminopropyl)imidazole to hexamethylene diisocyanate, followed by adding the first organic solvent. In the present invention, the dropwise addition rate is preferably 5 to 20 drops / min, more preferably 10 drops / min. The dropwise addition method of the present invention allows for control of the reaction rate.

[0045] In the present invention, the temperature of the ureaylation reaction is preferably 75-85°C, more preferably 80°C; the time is preferably 3-5 hours, more preferably 4 hours. In the present invention, the atmosphere of the ureaylation reaction is preferably air atmosphere.

[0046] After obtaining the urea-functionalized imidazole salt, the present invention mixes the urea-functionalized imidazole salt with an alkyl halide and performs a quaternization reaction to obtain the urea-functionalized imidazole salt having a long alkyl chain structure. In the present invention, the molar ratio of the urea-functionalized imidazole salt to the alkyl halide is preferably 1:2 to 2.2. In the present invention, the alkyl halide preferably includes one or more of an alkyl bromide, an alkyl chloride, and an alkyl iodide; the alkyl bromide preferably includes dodecane bromide or hexadecane bromide.

[0047] In the present invention, the temperature of the quaternization reaction is preferably 75-85°C, more preferably 80°C; the time is preferably 8-48 hours, more preferably 20-30 hours, and further preferably 24 hours. In the present invention, the atmosphere of the quaternization reaction is preferably air.

[0048] In the present invention, after the quaternization reaction, the obtained solid product is preferably washed with petroleum ether to obtain a urea-functionalized imidazole salt having a long alkyl chain structure.

[0049] After obtaining the urea-functionalized imidazole salt with a long alkyl chain structure, the present invention mixes the urea-functionalized imidazole salt with a long alkyl chain structure, sodium salt of dioctyl sulfosuccinate and a second organic solvent, and performs an ion exchange reaction to obtain the functionalized urea-functionalized gemini imidazole docusate salt. In the present invention, the molar ratio of the urea-functionalized imidazole salt with a long alkyl chain structure and sodium salt of dioctyl sulfosuccinate is preferably 1:2 to 2.2. In the present invention, the second organic solvent preferably includes acetonitrile, methanol or isopropanol, more preferably acetonitrile. In the present invention, the amount ratio of the urea-functionalized imidazole salt with a long alkyl chain structure and the second organic solvent is preferably 0.1 mol:140 to 160 mL.

[0050] In the present invention, the temperature of the ion exchange reaction is preferably 75-85°C, more preferably 80°C; the time is preferably 8-48 hours, more preferably 20-30 hours, and further preferably 24 hours. In the present invention, the atmosphere of the ion exchange reaction is preferably air.

[0051] In the present invention, after the ion exchange reaction, the process preferably further comprises: subjecting the resulting system to vacuum distillation to remove the organic solvent, extracting the residue with dichloromethane to obtain an organic phase; and drying the organic phase to obtain the functionalized ureido gemini imidazole docusate salt. The specific operations of the vacuum distillation and dichloromethane extraction are not particularly limited in the present invention, and methods well known to those skilled in the art may be employed.

[0052] The present invention provides applications of the functionalized urea-based gemini imidazole docusate salt described in the above technical solution, or the functionalized urea-based gemini imidazole docusate salt prepared by the preparation method described in the above technical solution, in the fields of lubrication, rust prevention, or corrosion inhibition. In the present invention, the applications preferably include: using the functionalized urea-based gemini imidazole docusate salt as a lubricant additive or a rust preventive oil additive; or using the functionalized urea-based gemini imidazole docusate salt as one or more of a lubricant, corrosion inhibitor, and rust inhibitor.

[0053] In the present invention, the application is preferably applied to the protection of a metal substrate; the elements of the metal substrate preferably include at least one of iron, copper and aluminum. In a specific embodiment of the present invention, the metal substrate is carbon steel.

[0054] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0055] Example 1

[0056] 0.1 mol of 1-(3-aminopropyl)imidazole was added dropwise to 0.05 mol of 1,6-hexanediisocyanate at a rate of 10 drops / min, 150 mL of acetonitrile was added, and a urea-formation reaction was carried out at 80°C for 4 hours; 0.1 mol of hexadecane bromide was added, and a quaternization reaction was carried out at 80°C for 24 hours. The obtained solid product was washed with petroleum ether to obtain a urea-functionalized imidazole salt with a long alkyl chain structure; 0.1 mol of sodium dioctyl sulfosuccinate (CAS: 577-11-7) was added to the urea-functionalized imidazole salt with a long alkyl chain structure, 150 mL of acetonitrile was added, and an ion exchange reaction was carried out at 80°C for 24 hours; the obtained product was distilled under reduced pressure to remove the solvent, the organic phase was extracted with dichloromethane, and the obtained organic phase was dried to obtain a functionalized urea-functionalized gemini imidazole docusate salt (2M16-DOSS).

[0057] The cation of 2M16-DOSS prepared in this example is The anion is The molar ratio of the cation to the anion is 1:2.

[0058] The 2M16-DOSS prepared in this example is a light yellow liquid molten salt, and the characterization results are as follows:

[0059] The hydrogen spectrum data is: 1H NMR(400MHz, CDCl3)δ:9.47(s,2H),7.80(s,2H),7.20(s,2H),6.28(s,2H),5.91(s,2H),5.29(s,2H),4.37(t,J=8.0Hz,8H),4.23 -4.15(m,8H),4.07-3.91(m,8H),3.26-3.08(m,18H),2.02(t,J=8.0Hz,6H),1.87(s,6H),1.63-1.25(m,86H),0.88-0.83(m,30H).

[0060] The carbon spectrum data are: 13 C NMR(100MHz, CDCl3)δ:171.37,169.04,159.64,67.93,67.86,67.28,62.07,38.68,38.58,31.92,30.29,30.15,3 0.08,29.70,29.65,29.56,29.42,29.35,29.04,28.89,26.34,23.67,23.47,22.95,22.68,14.09,14.06,14.03.

[0061] The mass spectrometry data are shown in Table 1:

[0062] Table 1 Mass spectrometry data of 2M16-DOSS

[0063]

[0064] Test Case

[0065] (1) Sample preparation

[0066] The 2M16-DOSS prepared in Example 1 was dissolved in the common mineral oil MVI 150 to prepare a uniform and stable lubricating system. 2M16-DOSS lubricating systems were prepared by adding 0.5 wt%, 1.0 wt%, and 2.0 wt% of 2M16-DOSS to the MVI 150 base oil, respectively. The amounts of 2M16-DOSS and MVI 150 added are expressed in percentage by weight. For example, a 1.0 wt% 2M16-DOSS lubricating system means that, in 100 g of the 2M16-DOSS lubricating system, the mass fraction of 2M16-DOSS is 1% and the mass fraction of MVI 150 is 99%.

[0067] (2) Thermal stability

[0068] The kinematic viscosities of mineral oil MVI 150 and the prepared 2M16-DOSS lubricating system were measured using a SYP1003-III viscometer at 40°C and 100°C. Thermogravimetric analysis (TGA) was performed using a TA Instruments TGA-2950 instrument at a heating rate of 10°C / min under a nitrogen atmosphere.

[0069] A simultaneous thermal analyzer (STA) was used to measure the temperature range from room temperature to 600°C for MVI 150, a 0.5 wt% 2M16-DOSS lubricating system (0.5 wt% 2M16-DOSS), a 1.0 wt% 2M16-DOSS lubricating system (1.0 wt% 2M16-DOSS), and a 2.0 wt% 2M16-DOSS lubricating system (2.0 wt% 2M16-DOSS). As can be seen from Table 2, MVI 150 has a relatively high initial degradation temperature, while all lubricating system samples have initial decomposition temperatures greater than 220°C. This indicates that the lubricating systems obtained by adding 2M16-DOSS according to the present invention have high thermal stability.

[0070] (3) Viscosity-temperature performance

[0071] Table 2 lists the kinematic viscosity, viscosity index, and corresponding decomposition temperature at different thermal weight loss rates for MVI 150, a 0.5wt% 2M16-DOSS lubricating system, a 1.0wt% 2M16-DOSS lubricating system, and a 2.0wt% 2M16-DOSS lubricating system. The viscosity experiments show that after adding 2M16-DOSS, the samples exhibit a certain degree of viscosity reduction at addition levels of 0.5wt% and 1.0wt%. As the concentration of 2M16-DOSS increases to 2.0wt%, the sample viscosity exceeds that of MVI 150, reaching a maximum. This is because the dispersion of 2M16-DOSS in MVI 150 reaches saturation at a 2.0wt% addition level. This indicates that the lubricating system obtained by adding 2M16-DOSS of the present invention has better viscosity-temperature performance.

[0072] Table 2 Viscosity index and thermal weight loss temperature of MVI 150 and 2M16-DOSS lubrication systems

[0073]

[0074]

[0075] (4) Tribological properties of the 2M16-DOSS lubrication system

[0076] The tribological properties of the samples were evaluated using an SRV-IV friction and wear tester produced by Optimol Grease GmbH in Germany, using a ball-on-disc contact method. The friction tests were conducted at 25°C, with a frequency of 25 Hz, a load of 200 N, an amplitude of 1 mm, and a test time of 30 minutes in an air atmosphere. A GCr15 steel ball with a diameter of 10 mm and a GCr15 steel disc with a diameter of 24 mm and a thickness of 7.9 mm were used. The test results are shown in Table 3.

[0077] As shown in Table 3, the 2M16-DOSS lubrication system exhibits good friction reduction and anti-wear properties at room temperature (25°C) and high temperature (100°C). As can be seen from Table 3, at room temperature (25°C), the three concentrations of 2M16-DOSS lubrication systems effectively reduced the friction coefficient. The average friction coefficient of the samples with the addition of 2M16-DOSS was 0.118, which was 42% lower than that of MVI 150. Combined analysis shows that with the increase in the concentration of 2M16-DOSS, the wear volume of the lubrication system gradually decreases, reaching a limit at a concentration of 1.0wt%, corresponding to a reduction of about 54% in the wear volume. This shows that the addition of 2M16-DOSS at room temperature can effectively improve the friction reduction and anti-wear properties of MVI150.

[0078] At a high temperature of 100°C, the 2M16-DOSS lubrication system maintained its excellent lubrication performance. While the friction reduction performance of 2M16-DOSS deteriorated somewhat at high temperatures, it remained superior to that of the MVI 150 base oil. Compared to low-temperature conditions, the friction coefficient of the 2.0wt% concentration sample did not show a significant increase (increase of approximately 7.8%). Compared to the base oil, the average friction coefficient of the 2.0wt% 2M16-DOSS sample decreased by 34%. It can be observed that at a 2.0wt% concentration, 2M16-DOSS effectively reduced the wear volume of MVI 150 by approximately 62.4%, significantly different from the lower-concentration sample. Under the more demanding high-temperature environment, 2M16-DOSS demonstrated even greater friction reduction and anti-wear effectiveness. This is because the tribochemical reaction, catalyzed by high temperature, proceeds more rapidly, resulting in more 2M16-DOSS participating in the reaction process. The high 2M16-DOSS content produces more friction-reducing and anti-wear compounds, forming a tribochemical reaction film on the wear scar surface.

[0079] Table 3 Average friction coefficient and wear volume of 2M16-DOSS as a lubricant for steel / steel friction pairs

[0080]

[0081] (5) Corrosion inhibition performance of 2M16-DOSS

[0082] The corrosion inhibition performance of 2M16-DOSS was evaluated using electrochemical testing methods:

[0083] A 1 cm × 1 cm platinum electrode served as the counter electrode; an epoxy-coated iron disk electrode (>99.99% purity) with a diameter of 0.8 cm, leaving a 0.5 cm diameter exposed area, served as the working electrode; and saturated calomel was used as the reference electrode to form a three-electrode system. The three-electrode system was immersed in a solution of ethanol:H₂O = 2:1 (mass ratio). To obtain a stable open-circuit potential (OCP), the open-circuit potential (OCP) was recorded for 60 minutes. The Tafel parameters were E = Eocp ± 200 mV, with a scan rate of 0.333 mV / s.

[0084] To further verify the corrosion inhibition performance of 2M16-DOSS, Tafel polarization electrochemical experiments were conducted. Since 2M16-DOSS is insoluble in pure water, an ethanol-water solution (ethanol:H2O=2:1 (mass ratio)) was used as the solvent and corrosion medium. Figure 1 The anti-corrosion performance of 2M16-DOSS on iron in ethanol aqueous solution is shown. Figure 1 The "0%" in the figure represents an ethanol-water solution, while "0.5%," "1%," and "2%" represent the mass concentration of 2M16-DOSS in the ethanol-water solution. Compared to the ethanol-water solution, the corrosion current density of 2M16-DOSS is generally lower. Generally speaking, a higher corrosion potential indicates a lower corrosion tendency, and a higher corrosion current density indicates a greater degree of corrosion. In the experiment, as the concentration of 2M16-DOSS in the ethanol-water solution increased, the corrosion potential shifted positively and the corrosion current density decreased significantly, demonstrating good corrosion resistance. This indicates that 2M16-DOSS effectively improves the corrosion resistance of iron. The enhanced corrosion resistance is attributed to the fact that 2M16-DOSS forms a protective film on the substrate surface through the coordination of the urea functional group with the iron surface. The unique long carbon chain structure of the imidazole ring of 2M16-DOSS effectively isolates the corrosive environment, thereby preventing the corrosion of the iron.

[0085] (6) Lubrication and corrosion inhibition properties of 2M16-DOSS anti-rust oil

[0086] To verify the lubrication and corrosion inhibition effects of 2M16-DOSS, a series of rust preventive oils with different addition amounts of 2M16-DOSS were prepared. The formulas are as follows: the addition amounts of 2M16-DOSS are 0%, 1wt%, 2wt%, and 3wt%, respectively; the addition amount of neutral barium dinonylnaphthalenesulfonate (T705A) is 7.0wt%; the addition amount of lanolin magnesium soap is 2.0wt%; the addition amount of sorbitan monooleate (Span80) is 2.5wt%; the addition amount of 2,6-di-tert-butyl-p-methylphenol (T501) is 0.5wt%; the addition amount of A51 base oil is 5.0wt%; and MVI 150 is the balance.

[0087] 1) Lubrication performance was tested on a four-ball friction tester in accordance with GB / T 3142-2019. The results are shown in Table 4. In Table 4, "rust-proof base oil" refers to a rust-proof oil with a 0% addition of 2M16-DOSS, "rust-proof base oil + 1 wt% 2M16-DOSS" refers to a rust-proof oil with a 1 wt% addition of 2M16-DOSS, "rust-proof base oil + 2 wt% 2M16-DOSS" refers to a rust-proof oil with a 2 wt% addition of 2M16-DOSS, and "rust-proof base oil + 3 wt% 2M16-DOSS" refers to a rust-proof oil with a 3 wt% addition of 2M16-DOSS.

[0088] Table 4 Average friction coefficient and average wear spot diameter of 2M16-DOSS anti-rust oil

[0089]

[0090] As can be seen from Table 4, the anti-rust oil sample (anti-rust base oil) without the addition of 2M16-DOSS has poor friction reduction performance, with an average friction coefficient of about 0.106. After adding 1wt% 2M16-DOSS, the friction reduction performance of the anti-rust oil is improved. When the mass fraction of 2M16-DOSS increases to more than 2wt%, the friction reduction of the anti-rust oil is significantly improved. The average friction coefficient of 2wt% 2M16-DOSS lubrication is about 0.09, and the average friction coefficient of 3wt% 2M16-DOSS lubrication is about 0.08, which are 5.1% and 13.83% lower than the anti-rust base oil, respectively. Analysis of the average wear spot diameter data shows that as the amount of 2M16-DOSS added increases, the average wear spot diameter decreases, indicating that the formulated anti-rust oil has a certain anti-wear effect and effectively reduces the wear volume. Compared with the anti-rust base oil, all samples effectively reduced the wear volume.

[0091] 2) Corrosion resistance

[0092] The corrosion resistance of the 2M16-DOSS rust-proof oil prepared above was characterized by using the salt spray hanging board test. The steel sheet was vertically hung in the rust-proof oil sample, pulled out and left to stand for 3 hours to allow the rust-proof oil to be evenly distributed on the surface of the steel sheet. Four groups of samples with different 2M16-DOSS concentrations (0%, 1wt%, 2wt%, 3wt%) were prepared. In the salt spray corrosion test, the rust-proof oil with 2M16-DOSS (1wt%, 2wt%, 3wt%) showed relatively superior corrosion resistance. Observation Figure 2 It can be seen that after 50 hours of salt spray test, no obvious signs of rust appeared on the surface of the four groups of samples. After the salt spray test continued for 100 hours, obvious pitting corrosion appeared on the surface of the sample without adding 2M16-DOSS, while the surfaces of the 2M16-DOSS samples with three concentrations of 1wt%, 2wt%, and 3wt% remained intact, indicating that 2M16-DOSS played a good role as a rust inhibitor. When the salt spray test continued for 150 hours, signs of rust appeared on the surface of all samples, the surface of the rust-proof base oil sample was corroded in large areas, and the surface of the sample with 2M16-DOSS added only showed pitting corrosion. The above phenomena show that 2M16-DOSS has outstanding anti-corrosion properties as a rust-proof oil additive.

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A functionalized urea-based gemini imidazole docusate salt comprising a cation and an anion; the molar ratio of the cation to the anion is 1:2; The cation has a structure shown in Formula I: In the formula I, R is C1 to C 18 Alkyl; The anion has a structure shown in Formula II:

2. The functionalized urea-based gemini imidazole docusate salt according to claim 1, characterized in that The R is methyl, ethyl, propyl, butyl, isobutyl, pentyl, isopentyl, octyl, isooctyl, decyl, isodecyl, dodecyl, tetradecyl, hexadecyl or octadecyl.

3. The method for preparing the functionalized urea-based gemini imidazole docusate salt according to any one of claims 1 to 2, comprising the following steps: mixing hexamethylene diisocyanate, 1-(3-aminopropyl)imidazole and a first organic solvent to carry out a ureidation reaction to obtain a urea-functionalized imidazole salt; Mixing the urea-functionalized imidazole salt and an alkyl halide, and performing a quaternization reaction to obtain a urea-functionalized imidazole salt having an alkyl chain structure; The urea-functionalized imidazole salt having an alkyl chain structure, sodium salt of dioctyl sulfosuccinate, and a second organic solvent are mixed to perform an ion exchange reaction to obtain the functionalized urea-functionalized gemini imidazole docusate salt; The urea-functionalized imidazole salt has a structure shown in Formula III:

4. The preparation method according to claim 3, characterized in that The molar ratio of the 1,6-hexamethylene diisocyanate to 1-(3-aminopropyl)imidazole is 1:

2.

5. The preparation method according to claim 3 or 4, characterized in that The temperature of the urea formation reaction is 75-85° C., and the time is 3-5 hours.

6. The preparation method according to claim 3, characterized in that The molar ratio of the urea-functionalized imidazole salt to the alkyl halide is 1:2 to 2.

2.

7. The preparation method according to claim 3 or 6, characterized in that The temperature of the quaternization reaction is 75-85° C., and the time is 8-48 hours.

8. The preparation method according to claim 3, characterized in that The molar ratio of the urea functionalized imidazole salt with an alkyl chain structure to the sodium salt of dioctyl sulfosuccinate is 1:2 to 2.

2.

9. The preparation method according to claim 3 or 8, characterized in that The temperature of the ion exchange reaction is 75-85° C., and the time is 8-48 hours.

10. Use of the functionalized urea-based gemini imidazole docusate salt according to any one of claims 1 to 2 or the functionalized urea-based gemini imidazole docusate salt prepared by the preparation method according to any one of claims 3 to 9 in the fields of lubrication, rust prevention or corrosion inhibition.

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