An ionic liquid lubricant prepared in situ in water and a preparation method thereof

Abstract

The present invention provides an ionic liquid lubricant prepared in situ in water and a preparation method thereof, the method comprising: stirring a phytic acid aqueous solution and a compound containing an alcoholic hydroxyl group at room temperature to obtain the lubricant. The raw material phytic acid used in the present invention is extracted from plants, does not contain halogens, is not easy to decompose corrosive acids such as HF, does not contain S, reduces corrosion to metals such as copper, and has low toxicity; moreover, since phytic acid has strong acidity, it can be stirred with a compound containing an alcoholic hydroxyl group at room temperature to directly react to generate an ionic liquid, and the preparation method is simple and time-consuming. This aqueous ionic liquid does not need to be dried, can be directly used as a lubricant, and has good anti-corrosion performance.

Description

Technical Field

[0001] The invention relates to the technical field of materials, and in particular to an ionic liquid lubricant prepared in situ in water and a preparation method thereof. Background Art

[0002] Ionic liquids have the advantages of low volatility, high reactivity, strong surface adsorption capacity, and controllable structure and properties, and can be used as high-performance lubricants and lubricant additives.

[0003] However, conventional ionic liquids are halogen-containing ionic liquids, which are easily hydrolyzed to produce corrosive acids such as HF and HCl and have high toxicity. Therefore, conventional ionic liquids are mainly used as lubricants for non-metallic materials such as ceramics, which limits the application scope of conventional ionic liquids. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of traditional ionic liquids, such as high toxicity, poor hydrolysis stability and strong corrosiveness, and to provide an ionic liquid lubricant prepared in situ in water and a preparation method thereof.

[0005] The invention discloses a method for preparing an ionic liquid lubricant in situ in water. The phytic acid aqueous solution and a compound containing alcoholic hydroxyl group are stirred and reacted at room temperature to obtain the lubricant.

[0006] Furthermore, in the method for in-situ preparation of ionic liquid lubricants in water as described above, the compound containing alcoholic hydroxyl groups includes one or more of monoethanolamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine, and choline hydroxide.

[0007] Furthermore, in the method for in-situ preparation of ionic liquid lubricants in water as described above, the concentration of the phytic acid aqueous solution is 50%-90%.

[0008] An ionic liquid lubricant prepared by any of the above methods.

[0009] Beneficial effects:

[0010] The raw material phytic acid used in the present invention is extracted from plants, does not contain halogen, is not easy to decompose corrosive acids such as HF, does not contain S, reduces corrosion to metals such as copper, and has low toxicity; moreover, since phytic acid has strong acidity, it can be stirred with a compound containing an alcoholic hydroxyl group at room temperature to directly react to generate an ionic liquid, and the preparation method is simple and time-consuming. The aqueous ionic liquid does not need to be dried, can be directly used as a lubricant, and has good anti-corrosion performance.

[0011] In addition, the present invention can obtain lubricants containing ionic liquids with different tribological properties by regulating the water content. The mechanism of action is that the anion and cation structures formed by the ionic liquid in water are adsorbed on the metal surface with positive charge in the form of ion pairs, thereby forming a more dense and ordered adsorption film with a double electric layer structure. The adsorption film not only isolates water and air, but also improves the metal's anti-corrosion performance. Moreover, the regulation of the water content can change the viscosity and shear properties of the adsorption film, thereby controlling its friction performance as a lubricant. In addition, during the friction process, the molecular active groups containing P elements in the adsorption film can further react with the metal to generate a friction reaction film. The boundary lubrication film composed of the adsorption film and the friction reaction film has good shear and wear resistance, thereby further reducing the friction coefficient and reducing wear, and effectively improving the lubrication performance of the lubricant. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is the friction coefficient curve of phytic acid ionic liquid with different water contents;

[0013] Figure 2 This is a diagram showing the anti-corrosion effect of phytic acid ionic liquid of different concentrations on cast iron. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Embodiment 1:

[0016] 100.0 g of 70 wt % phytic acid aqueous solution and 149.2 g of triethanolamine were stirred and reacted at room temperature for 2 h to obtain an aqueous 10 wt % phytic acid ionic liquid. The following formula is the molecular structure of the ionic liquid prepared in this example.

[0017]

[0018] Embodiment 2:

[0019] 100.0 g of 70 wt % phytic acid aqueous solution and 149.2 g of triethanolamine were reacted in 15.9 g of water under stirring at room temperature for 2 h to obtain an aqueous 15 wt % phytic acid ionic liquid.

[0020] Embodiment 3:

[0021] 100.0 g of 70 wt % phytic acid aqueous solution and 149.2 g of triethanolamine were reacted in 35.0 g of water under stirring at room temperature for 2 h to obtain an aqueous phytic acid ionic liquid containing 20 wt % of phytic acid.

[0022] Embodiment 4:

[0023] 100.0 g of 70 wt % phytic acid aqueous solution and 149.2 g of triethanolamine were reacted in 56.6 g of water under stirring at room temperature for 2 h to obtain an aqueous phytic acid ionic liquid containing 25 wt % of phytic acid.

[0024] Embodiment 5:

[0025] 100.0 g of 70 wt % phytic acid aqueous solution and 149.2 g of triethanolamine were reacted in 81.4 g of water under stirring at room temperature for 2 h to obtain an aqueous 30 wt % phytic acid ionic liquid.

[0026] Embodiment 6:

[0027] 100.0 g of 70 wt % phytic acid aqueous solution and 149.2 g of triethanolamine were reacted in 109.9 g of water under stirring at room temperature for 2 h to obtain an aqueous phytic acid ionic liquid containing 35 wt % of phytic acid.

[0028] Embodiment 7:

[0029] 100.0 g of 70 wt % phytic acid aqueous solution and 149.2 g of triethanolamine were reacted in 143.2 g of water under stirring at room temperature for 2 h to obtain an aqueous phytic acid ionic liquid containing 40 wt % of phytic acid.

[0030] Embodiment 8:

[0031] 100.0 g of 70 wt % phytic acid aqueous solution and 149.2 g of triethanolamine were reacted in 182.6 g of water under stirring at room temperature for 2 h to obtain a phytic acid ionic liquid containing 45 wt % of water.

[0032] Experimental Example 1:

[0033] Tribological performance test:

[0034] The friction coefficient was evaluated using the SRV-IV micro-motion friction and wear tester from Optimol Grease Company of Germany at a temperature of 30°C, a frequency of 50Hz, an amplitude of 1mm, a load of 5N, and a time of 30min. The steel ball used in the test was a GCr15 bearing steel with a diameter of 10mm, and the block used for the lower specimen was a GCr15 steel block with a diameter of 24mm and a height of 7.9±0.1mm. The wear volume of the wear scar on the steel block was measured using a non-contact 3D surface profiler. Figure 1 The friction coefficient curves of phytic acid ionic liquids with different water contents are shown in Figure 2. Figure 1 As shown, through Figure 1It can be seen that when the water content exceeds 25%, the higher the water content, the greater the friction coefficient, and the friction coefficient reaches the minimum value when the water content is 25%.

[0035] The average friction coefficient and wear volume results are shown in Table 1, where the comparative example is water. As can be seen from Table 1, the ionic liquids prepared in Examples 1-4 have good friction reduction and anti-wear properties. However, as the water content increases, the viscosity decreases and the corresponding corrosion wear increases, and the friction reduction and anti-wear properties of the ionic liquids prepared in Examples 5-8 become worse.

[0036]

[0037] Experimental Example 2:

[0038] Anti-corrosion performance test:

[0039] This experimental example uses the cast iron sheet corrosion in GB / T 6144-2010 for corrosion resistance testing. Figure 2 The phytic acid ionic liquid prepared by the method of the present invention has a good anti-corrosion effect on cast iron in the embodiments with a water content of 15%-45%.

[0040] Furthermore, when the water content of the phytic acid ionic liquid is between 10% and 30%, the SRV friction test results show that the embodiment with a water content of 10%-30% has better anti-wear performance and a lower friction coefficient, and when the water content exceeds 30%, the wear amount increases sharply.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for in-situ preparation of ionic liquid lubricants in water, characterized in that: The phytic acid aqueous solution and the compound containing alcoholic hydroxyl group are stirred and reacted at room temperature to obtain the product; The phytic acid is extracted from plants; The compound containing alcoholic hydroxyl group includes: one or more of monoethanolamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine, and choline hydroxide; The concentration of the phytic acid aqueous solution is 50%-90%.

2. An ionic liquid lubricant prepared by the method according to claim 1.

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