A piperazine ionic liquid and its preparation method and application

Abstract

The present invention relates to a piperazine ionic liquid, which has the following structural formula: wherein: the R group is a methyl group and an ethyl group. At the same time, the present invention also discloses a preparation method and application of the piperazine ionic liquid. The preparation method of the present invention is simple, and the piperazine ionic liquid exhibits excellent lubrication and anti-wear properties as a lubricant, and can be used as a space lubricant on a spacecraft motion mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricants, and in particular to a piperazine ionic liquid and a preparation method and application thereof. Background Art

[0002] The rapid development of aerospace technology has made the demand for long life and reliability of spacecraft more urgent, so the study of space tribology is particularly important. In early space activities, the operation time of spacecraft was generally short. Subsequent research at the National Aeronautics and Space Administration of the United States showed that many mechanical failures on spacecraft were caused by tribological problems, especially failures related to lubrication. With the continuous advancement of lubrication technology, lubrication technology has become one of the key technologies to ensure the safe and reliable operation of mechanical parts and extend their service life. Therefore, whether it is a satellite, rocket, spacecraft or space station, the development of lubrication materials and technologies is crucial and should not be underestimated. In order to meet the needs of the development of space science and technology in my country, it is of great significance to carry out systematic research on space lubricants, which shows broad application prospects.

[0003] Ionic liquids are a class of ionic compounds composed of organic cations and organic or inorganic anions that are liquid at room temperature. Ionic liquids have unique physical and chemical properties, such as extremely low saturated vapor pressure, wide liquid range, high thermal stability, and structural designability. These properties make them have great potential as high-performance lubricants or additives, especially in the wide application of space. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a stable piperazine ionic liquid with good lubricity.

[0005] Another technical problem to be solved by the present invention is to provide a method for preparing the piperazine ionic liquid.

[0006] The third technical problem to be solved by the present invention is to provide the application of the piperazine ionic liquid.

[0007] In order to solve the above problems, the present invention provides a piperazine ionic liquid, characterized in that the ionic liquid has the following structural formula:

[0008]

[0009] Among them: R groups are methyl and ethyl.

[0010] The preparation method of a piperazine ionic liquid as described above is characterized in that: the method refers to adding excess anhydrous ethanol to N-alkylpiperazine to dissolve it, then slowly adding di(2-ethylhexyl) phosphate, stirring at room temperature for 20 to 24 hours to obtain a mixed solution; the mixed solution is subjected to rotary evaporation to remove anhydrous ethanol and then dried at 80 to 90° C. for 12 to 18 hours to obtain a piperazine ionic liquid.

[0011] Its synthetic route is as follows:

[0012]

[0013] The N-alkylpiperazine refers to N-methylpiperazine or N-ethylpiperazine.

[0014] The molar ratio of the N-alkylpiperazine to the di(2-ethylhexyl)phosphate is 1:1.

[0015] The application of the piperazine ionic liquid as described above is characterized in that the piperazine ionic liquid is used as a space lubricant in the motion mechanism of a spacecraft.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. The preparation method of the present invention is simple. An ionic liquid is designed and synthesized that does not contain active elements such as sulfur and halogen that may corrode metal friction pairs, thereby solving the problem of lubricant corrosion of spacecraft motion mechanisms.

[0018] 2. The piperazine ionic liquid described in the present invention is used as a liquid lubricant. Compared with the aerospace lubricant PFPE, it has good and stable lubrication performance in a vacuum environment. Its friction reduction and anti-wear performance in a harsh vacuum environment is particularly outstanding, thereby solving the problems of friction, wear and poor lubrication during the operation of space machinery and equipment.

[0019] 3. The piperazine ionic liquid of the present invention has excellent lubrication performance and environmentally friendly characteristics, which makes it have broad application prospects in lubrication engineering and space fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0021] Figure 1 This is the H-NMR spectrum of [1-MPip][DEHP] of the present invention.

[0022] Figure 2 This is the H-NMR spectrum of [1-EPip][DEHP] of the present invention.

[0023] Figure 3The OM image and microscopic morphology SEM image of the wear spot of the piperazine ionic liquid and PFPE under high vacuum and room temperature of the present invention are shown in FIG.

[0024] Figure 4 The OM image and microscopic SEM image of the wear spot of the piperazine ionic liquid and PFPE under high vacuum and high temperature of the present invention are shown in FIG. 1 , wherein: the left one is [1-MPip][DEHP]; the middle one is [1-EPip][DEHP]; the right one is PFPE. DETAILED DESCRIPTION

[0025] A piperazine ionic liquid, characterized in that the ionic liquid has the following structural formula:

[0026]

[0027] Among them: R groups are methyl and ethyl.

[0028] A preparation method of a piperazine ionic liquid comprises the steps of adding an excess of anhydrous ethanol to N-alkylpiperazine to dissolve the mixture, then slowly dropping di(2-ethylhexyl) phosphate, stirring the mixture at room temperature for 20 to 24 hours, and obtaining a mixed solution; after the anhydrous ethanol is removed by rotary evaporation, the mixed solution is dried in a vacuum drying oven at 80 to 90° C. for 12 to 18 hours, and thus obtaining the piperazine ionic liquid.

[0029] Wherein: N-alkylpiperazine refers to N-methylpiperazine or N-ethylpiperazine.

[0030] The molar ratio of N-alkylpiperazine to the di(2-ethylhexyl)phosphate is 1:1.

[0031] The invention discloses an application of a piperazine ionic liquid, wherein the piperazine ionic liquid is used as a space lubricant in a spacecraft motion mechanism.

[0032] Example 1

[0033] Take 5.00 g of N-methylpiperazine in a 250 mL single-necked flask, add excess anhydrous ethanol to dissolve, then slowly drop 16.12 g of di(2-ethylhexyl) phosphate into the round-bottom flask and stir at room temperature for 20 h. The obtained solution was rotary evaporated to remove anhydrous ethanol. Finally, it was dried at 80 ° C in a vacuum drying oven for 12 h to obtain a piperazine ionic liquid, recorded as [1-MPip][DEHP].

[0034] The NMR spectrum of [1-MPip][DEHP] is as follows Figure 1 shown.

[0035] 1H NMR (chloroform-d, 600 MHz) δ 0.74 - 1.0 (m,12H, -CH3), δ 1.18 -1.57 (m, 18H, -CH2-, -CH-), δ 2.24 - 2.41 (s, 3H, N-CH3), δ 2.56 - 2.74 (s,4H, N-CH2-), δ 3.0 - 3.2 (t, 4H, N + -CH2-), δ 3.63 - 3.80 (m, 4H, O-CH2-), δ10.15 - 10.84 (s, NH2 + )

[0036] Example 2

[0037] Take 7.99 g of N-ethylpiperazine in a 250 mL single-necked flask, add excess anhydrous ethanol to dissolve, then slowly drop 22.57 g of di(2-ethylhexyl) phosphate into the round-bottom flask and stir at room temperature for 24 h. The obtained solution was rotary evaporated to remove anhydrous ethanol. Finally, it was dried at 90 ° C in a vacuum drying oven for 18 h to obtain a piperazine ionic liquid, recorded as [1-EPip][DEHP].

[0038] The H NMR spectrum of [1-EPip][DEHP] is as follows Figure 2 shown.

[0039] 1 H NMR (chloroform-d, 600 MHz) δ 0.72 - 0.98 (m,12H, -CH3), δ 1.0 -1.15 (t, 3H, NC-CH3), δ 1.17 - 1.59 (m, 18H, -CH2-, -CH-), δ 2.39-2.52 (m,2H, N-CH2-) δ 2.57 - 2.80 (s, 4H, N-CH2-), δ 3.0 - 3.19 (t, 4H, N + -CH2-) δ3.54 - 3.82 (m, 4H, O-CH2-), δ 10.16 - 10.86 (s, NH2 + )

[0040] Application of piperazine ionic liquids as liquid lubricants

[0041] Tribological properties test of piperazine ionic liquids at high vacuum at 25°C:

[0042] The lubricating performance of [1-MPip][DEHP] and [1-EPip][DEHP] as lubricants of the present invention was investigated on a VFBT-4000 vacuum four-ball tester. In order to verify its superiority, aerospace lubricant perfluoropolyether (PFPE) was subjected to a comparative test.

[0043] The friction test lasted for 30 min at a temperature of 25 °C, a load of 392 N, and a rotation speed of 1450 r / min. The upper and lower test balls used in the experiment were GCr15 steel balls. The friction test results are shown in Table 1.

[0044] Table 1 Comparison of friction coefficient and wear spot diameter between piperazine ionic liquid and PFPE

[0045]

[0046] It can be seen from Table 1 that the friction coefficient and wear spot diameter of piperazine ionic liquids are much lower than those of PFPE, and the longer the alkyl chain, the better the anti-wear performance.

[0047] After the friction test, the optical microscope (OM) and scanning electron microscope (SEM) were used to detect the wear surface morphology of the test ball. Figure 3 From the OM and SEM images, it can be seen that the PFPE wear spots are larger and there are obvious plowing grooves on the surface.

[0048] Experiments show that the lubrication performance of piperazine ionic liquids is better than that of PFPE at high vacuum at 25°C, and they have good friction reduction and anti-wear properties.

[0049] Tribological properties test of piperazine ionic liquids at 75°C in high vacuum:

[0050] The lubricating properties of [1-MPip][DEHP] and [1-EPip][DEHP] as lubricants of the present invention were investigated using a VFBT-4000 vacuum four-ball testing machine, and a comparative test was conducted with aerospace lubricant perfluoropolyether (PFPE).

[0051] The selected load is 392 N, the temperature is 75℃, the speed is 1450 r / min, the test time is 30 min, and the upper and lower test balls are GCr15 steel balls. The vacuum friction test results are shown in Table 2.

[0052] Table 2 Comparison of friction coefficient and wear spot diameter between piperazine ionic liquid and PFPE

[0053]

[0054] It can be seen from Table 2 that the friction coefficient and wear spot diameter of piperazine ionic liquids are much lower than those of PFPE.

[0055] After the friction test, the wear surface of the test ball was examined by optical microscopy (OM) and scanning electron microscopy (SEM). Figure 4 From the OM and SEM images, it can be seen that the PFPE wear spots are larger and there are obvious plowing grooves on the surface.

[0056] In summary, compared with aerospace lubricant PFPE, the piperazine ionic liquid of the present invention exhibits excellent lubrication and anti-wear properties as a lubricant, and can be used as a space lubricant on the motion mechanism of a spacecraft.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A piperazine ionic liquid, characterized in that: The ionic liquid has the following structural formula: Among them: R groups are methyl and ethyl.

2. The method for preparing a piperazine ionic liquid according to claim 1, wherein: The method comprises the steps of adding excess anhydrous ethanol to N-alkylpiperazine to dissolve the mixture, then slowly dropping di(2-ethylhexyl) phosphate, stirring the mixture at room temperature for 20 to 24 hours, and obtaining a mixed solution; after the anhydrous ethanol is removed by rotary evaporation, the mixed solution is dried at 80 to 90° C. for 12 to 18 hours to obtain a piperazine ionic liquid; the N-alkylpiperazine refers to N-methylpiperazine or N-ethylpiperazine.

3. The method for preparing a piperazine ionic liquid according to claim 2, wherein: The molar ratio of the N-alkylpiperazine to the di(2-ethylhexyl)phosphate is 1:

1.

4. The use of a piperazine ionic liquid as claimed in claim 1, characterized in that: The piperazine ionic liquid is used as a space lubricant in the motion mechanism of a spacecraft.

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