A caffeate ionic liquid and a preparation method and application thereof

Abstract

The present application relates to a kind of caffeic acid salt ionic liquid, the structure of the caffeic acid salt ionic liquid is as follows: Wherein: R1 group is one of n-butyl, n-hexyl or n-octyl.Simultaneously, the preparation method and application of the caffeic acid salt ionic liquid are disclosed.The preparation method of the present application is simple, and the obtained ionic liquid has good lubricating property, and the caffeic acid salt ionic liquid as additive can significantly improve the structural strength and tribological property of composite titanium base grease at lower content, and is expected to be widely used as grease additive in lubricating engineering and industrial field.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lubricating additives, in particular to a caffeic acid salt ionic liquid and a preparation method and application thereof. BACKGROUND

[0002] Friction, wear and lubrication have been the problems needed to be researched and solved in the development of human society, a large number of mechanical friction parts are in boundary lubrication state in operation, and the load is almost entirely borne by the boundary lubrication film generated by the interaction between the microconvex and the lubricating material and the surface, and ordinary lubricating materials may cause serious friction and wear, so there is a higher requirement for the service performance of the lubricating material under harsh conditions.

[0003] The addition of additives can improve the quality of lubricating materials and endow them with new key performance, and is an indispensable component of high-end equipment lubricating materials. With the progress of science and technology, it is urgent to prolong the service life of mechanical equipment and reduce energy consumption, and the preparation of new additives is the need of the times. Ionic liquid refers to an ionic compound composed of organic cations and organic / inorganic anions in a liquid state near room temperature. Its chemical stability and high thermal stability meet the needs of lubricating additives. At the same time, ionic liquids have unique properties and functions such as extremely low saturated vapor pressure, high thermal stability, strong structure designability and strong solubility. According to the designability of its structure, functional groups can be introduced into the structure of anion and cation, so as to design and synthesize ionic liquids with special functions, which are suitable for different service conditions. Therefore, ionic liquids have great potential as high-performance additives to realize wide application in the field of lubrication engineering. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a caffeic acid salt ionic liquid with good lubricating performance.

[0005] Another technical problem to be solved by the present application is to provide a preparation method of the caffeic acid salt ionic liquid.

[0006] A third technical problem to be solved by the present application is to provide an application of the caffeic acid salt ionic liquid.

[0007] To solve the above problems, the caffeic acid salt ionic liquid provided by the present application has the following structure:

[0008]

[0009] Wherein, the R1 group is one of n-butyl, n-hexyl or n-octyl.

[0010] The preparation method of the caffeic acid salt ionic liquid has the characteristics that caffeic acid and sodium bicarbonate are respectively completely dissolved in anhydrous ethanol and ultrasonically dispersed for 5-10 minutes, and caffeic acid ethanol solution with a concentration of 0.12 g / ml and sodium bicarbonate ethanol solution with a concentration of 0.17 g / ml are obtained; then the sodium bicarbonate ethanol solution is slowly added into the caffeic acid ethanol solution, and magnetic stirring reaction is carried out at room temperature for 8-12 hours to obtain a mixed solution; 1,3-dialkyl imidazole chloride is added into the mixed solution, and magnetic stirring reaction is carried out at room temperature for 24-36 hours; after the reaction is completed, white solids are precipitated, and the lower liquid is filtered, and then is sequentially subjected to rotary evaporation, washing, purification and vacuum drying to obtain the caffeic acid salt ionic liquid; the mass ratio of the sodium bicarbonate to the caffeic acid is 1:2.15; and the mass ratio of the 1,3-dialkyl imidazole chloride to the sodium bicarbonate is 1:0.35-0.50.

[0011] The application of the caffeic acid salt ionic liquid has the characteristics that the caffeic acid salt ionic liquid is uniformly stirred with a composite titanium-based lubricating grease, and then is ground by a three-roll mill for three times to obtain the lubricating grease.

[0012] The composite titanium-based lubricating grease is prepared by the following method: stearic acid and benzoic acid are dissolved in base oil at 90 DEG C, then isopropyl titanate is added, saponification reaction is carried out at 95 DEG C for 1 hour, deionized water is continuously added to carry out hydration reaction for 0.5 hour, the mixed system is continuously heated to 210 DEG C to carry out high-temperature refining for 5 minutes, and then the system is cooled to room temperature and ground by a three-roll mill for three times to obtain the composite titanium-based lubricating grease.

[0013] The mass ratio of the stearic acid, the benzoic acid, the base oil, the isopropyl titanate and the deionized water is 1:0.43:14.06:2:0.2.

[0014] The mass fraction of the caffeic acid salt ionic liquid in the lubricating grease is 0.5-2%.

[0015] Compared with the prior art, the application has the following advantages:

[0016] 1. The application designs a hydroxyl functionalized ionic liquid structure by referring to the unique organic molecular cation-anion structure of ionic liquids, and obtains the ionic liquid in liquid state at room temperature by simple ion exchange at room temperature.

[0017] 2. The preparation method is simple, the obtained ionic liquid has good lubricating performance, and does not contain elements such as sulfur, phosphorus and halogen, and the product after friction reaction has no pollution to natural environment such as water body and soil.

[0018] 3、The coffee acid salt ionic liquid as the additive can significantly improve the structural strength and tribological properties of the composite titanium base lubricating grease at a lower content, and is expected to be widely applied in the field of lubricating engineering and industry as a lubricating grease additive. BRIEF DESCRIPTION OF DRAWINGS

[0019] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0020] Figure 1 The viscoelasticity curves of the lubricating grease samples of the present application are shown in the figure, wherein a is [BMIM][CA], TCG, b is [HMIM][CA], TCG, c is [OMIM][CA], TGG, and d is [BMIM][SA], TCG.

[0021] Figure 2 The yield stress and cross stress columnar charts of the samples of the present application are shown in the figure, wherein a is [BMIM][CA], TCG, b is [HMIM][CA], TCG, c is [OMIM][CA], TGG, and d is [BMIM][SA], TCG. DETAILED DESCRIPTION

[0022] A coffee acid salt ionic liquid, which has the following structure:

[0023]

[0024] wherein the R1 group is one of n-butyl, n-hexyl or n-octyl.

[0025] The preparation method of the coffee acid salt ionic liquid is as follows: coffee acid and sodium bicarbonate are respectively completely dissolved in anhydrous ethanol and ultrasonically dispersed for 5-10 min, to obtain a coffee acid ethanol solution with a concentration of 0.12 g / ml and a sodium bicarbonate ethanol solution with a concentration of 0.17 g / ml; then the sodium bicarbonate ethanol solution is slowly added to the coffee acid ethanol solution, and the mass ratio (g / g) of sodium bicarbonate to coffee acid is 1:2.15. The mixture is subjected to magnetic stirring at room temperature for 8-12 h, and then 1,3-dialkyl imidazole chloride is added to the mixture, and the mass ratio (g / g) of 1,3-dialkyl imidazole chloride to sodium bicarbonate is 1:0.35-0.50. The mixture is subjected to magnetic stirring at room temperature for 24-36 h. After the reaction is completed, white solids are precipitated, and the lower layer liquid is filtered, and then subjected to rotary evaporation, washing, purification and vacuum drying in sequence, to obtain the coffee acid salt ionic liquid.

[0026] The application of the coffee acid salt ionic liquid is as follows: the coffee acid salt ionic liquid and the composite titanium base lubricating grease are uniformly stirred, and then ground by a three-roll mill for three times, to obtain the lubricating grease. The mass fraction of the coffee acid salt ionic liquid in the lubricating grease is 0.5-2%.

[0027] The composite titanium-based grease is prepared by the following method: stearic acid and benzoic acid are dissolved in base oil at 90°C, then isopropyl titanate is added, saponification is carried out at 95°C for 1 h, deionized water is continuously added to carry out hydration reaction for 0.5 h, the mixed system is continuously heated to 210°C to carry out high-temperature refining for 5 min, and after cooling to room temperature, three-roll grinding machine is used for grinding three times to obtain the composite titanium-based grease. The mass ratio (g / g) of stearic acid, benzoic acid, base oil, isopropyl titanate, and deionized water is 1:0.43:14.06:2:0.2.

[0028] Example 1

[0029] 18.02 g of caffeic acid is added to a flask and completely dissolved with 150 ml of anhydrous ethanol, and ultrasonic dispersion is carried out for 5 min. At the same time, 8.41 g of sodium bicarbonate is dissolved in 50 ml of anhydrous ethanol in the same way. Then the sodium bicarbonate ethanol solution is slowly added to the caffeic acid ethanol solution, and magnetic stirring is carried out at room temperature for 8 h. After the reaction is completed, 17.47 g of 1-butyl 3-methyl imidazole chloride salt is added, and magnetic stirring is carried out at room temperature for 24 h. After the reaction is completed, white solids are precipitated. Filtration is carried out, and after the lower liquid is subjected to rotary evaporation, washing, purification, and vacuum drying, 1-butyl-3-methyl imidazole caffeic acid salt ionic liquid is obtained, which is recorded as [BMIM][CA].

[0030] 5.69 g of stearic acid and 2.45 g of benzoic acid are dissolved in 80 g of 4016 base oil at 90°C, then 11.37 g of isopropyl titanate is added, saponification is carried out at 95°C for 1 h, 1.09 g of deionized water is continuously added to carry out hydration reaction for 0.5 h, the mixed system is continuously heated to 210°C, high-temperature refining is carried out for 5 min, and after cooling to room temperature, three-roll grinding machine is used for grinding three times to obtain the composite titanium-based grease, which is recorded as TCG.

[0031] 0.5 g of [BMIM][CA] is added to 99.5 g of TCG, and after being uniformly stirred, three-roll grinding is carried out three times to obtain a grease containing 0.5% of caffeic acid salt ionic liquid by mass fraction, which is recorded as TCG+0.5%[BMIM][CA].

[0032] Example 2

[0033] The preparation method of [BMIM][CA], TCG is the same as that in Example 1.

[0034] 1 g of [BMIM][CA] is added to 99 g of TCG, and after being uniformly stirred, three-roll grinding is carried out three times to obtain a grease containing 1% of caffeic acid salt ionic liquid by mass fraction, which is recorded as TCG+1%[BMIM][CA].

[0035] Example 3

[0036] [BMIM][CA], TCG preparation method same as Example 1.

[0037] Take 2 g [BMIM] [CA] into 98 g TCG, after fully stirring uniform, use three roll mill grinding three times, get the mass fraction of 2% of caffeic acid salt type ionic liquid grease, recorded as TCG + 2% [BMIM] [CA].

[0038] Example 4

[0039] Put 90.1 g caffeic acid into the flask, completely dissolved with 750 ml anhydrous ethanol, ultrasonic dispersion for 8 min. At the same time, 42.05 g sodium bicarbonate is dissolved in 250 ml anhydrous ethanol in the same way. Then slowly drop the sodium bicarbonate ethanol solution into the caffeic acid ethanol solution, and magnetically stir the reaction at room temperature for 10 h. After the reaction is completed, 101.4 g 1-hexyl 3-methyl imidazole chloride salt is added, and the reaction is magnetically stirred at room temperature for 30 h. After the reaction is completed, white solid is precipitated. After filtration, the lower liquid is taken out for rotary evaporation, washing, purification and vacuum drying, and 1-hexyl-3-methyl imidazole caffeic acid salt type ionic liquid is obtained, recorded as [HMIM] [CA].

[0040] Put 28.45 g stearic acid and 12.25 g benzoic acid into 400 g 4016 base oil at 90℃, then add 56.85 g titanium isopropylate to it, and carry out saponification reaction at 95℃ for 1 h, continue to add 5.45 g deionized water to carry out hydration reaction for 0.5 h, continue to heat the mixed system to 210℃, and high temperature refining for 5 min, then cool to room temperature, and use three roll mill to grind three times, to get composite titanium base grease, recorded as TCG.

[0041] Take 0.5 g [HMIM] [CA] into 99.5 g TCG, after fully stirring uniform, use three roll mill grinding three times, get the mass fraction of 0.5% of caffeic acid salt type ionic liquid grease, recorded as TCG + 0.5% [HMIM] [CA].

[0042] Example 5

[0043] [HMIM] [CA], TCG preparation method same as Example 4.

[0044] Take 1 g [HMIM] [CA] into 99 g TCG, after fully stirring uniform, use three roll mill grinding three times, get the mass fraction of 0.5% of caffeic acid salt type ionic liquid grease, recorded as TCG + 1% [HMIM] [CA].

[0045] Example 6

[0046] [HMIM][CA] was prepared in the same way as Example 4.

[0047] Take 2 g of [HMIM][CA] and add to 98 g of TCG, after fully stirring and uniform, use three roll mill grinding three times, to get the mass fraction of 0.5% of caffeic acid salt ionic liquid grease, recorded as TCG+2%[HMIM][CA].

[0048] Example 7

[0049] Take 36.04 g of caffeic acid into a flask, completely dissolved with 300 ml of anhydrous ethanol, ultrasonic dispersion for 10 min. At the same time, 16.82 g of sodium bicarbonate was dissolved in 100 ml of anhydrous ethanol in the same way. Then slowly drop the sodium bicarbonate ethanol solution into the caffeic acid ethanol solution, and magnetically stir the reaction at room temperature for 12 h. After the reaction is completed, 46.16 g of 1-octyl 3-methyl imidazole chloride salt is added, and the reaction is magnetically stirred at room temperature for 36 h. After the reaction is completed, white solid is precipitated. Filtration, take the lower liquid to spin, wash, purify, vacuum drying, 1-octyl-3-methyl imidazole caffeic acid salt ionic liquid is obtained, recorded as [OMIM][CA].

[0050] Take 28.45 g of stearic acid and 12.25 g of benzoic acid and dissolve in 400 g of 4016 base oil at 90°C, then add 56.85 g of titanium isopropyl to the mixture, and carry out saponification reaction at 95°C for 1 h, continue to add 5.45 g of deionized water to carry out hydration reaction for 0.5 h, continue to heat the mixture to 210°C, and high temperature refining for 5 min, then cool to room temperature and use three roll mill grinding three times, to get the composite titanium base grease, recorded as TCG.

[0051] Take 0.5 g of [OMIM][CA] and add to 99.5 g of TCG, after fully stirring and uniform, use three roll mill grinding three times, to get the mass fraction of 0.5% of caffeic acid salt ionic liquid grease, recorded as TCG+0.5%[OMIM][CA].

[0052] Example 8

[0053] [OMIM][CA] was prepared in the same way as Example 7.

[0054] TCG was prepared in the same way as Example 4.

[0055] Take 1 g [OMIM] [CA] into 99 g TCG, after fully stirring, use three roll mill to grind three times, get the grease containing 2% mass fraction of caffeic acid salt ionic liquid, recorded as TCG+1%[OMIM][CA].

[0056] Example 9

[0057] [OMIM][CA] preparation method is same with example 7.

[0058] TCG preparation method is same with example 4.

[0059] Take 2 g [OMIM] [CA] into 98 g TCG, after fully stirring, use three roll mill to grind three times, get the grease containing 2% mass fraction of caffeic acid salt ionic liquid, recorded as TCG+2%[OMIM][CA].

[0060] Comparative example 1

[0061] Put 13.82 g salicylic acid into a flask, completely dissolved with 100 ml anhydrous ethanol, ultrasonic dispersion for 10 min. At the same time, 8.41 g sodium bicarbonate is dissolved into 50 ml anhydrous ethanol in the same way. Then slowly drop the sodium bicarbonate ethanol solution into the caffeic acid ethanol solution, magnetic stirring at room temperature for 12 h. After the reaction is completed, 17.47 g 1-butyl 3-methyl imidazole chloride salt is added, and the reaction is carried out at room temperature for 36 h. After the reaction is completed, white solid is precipitated. Filtration, take the lower liquid to spin, wash, purify, vacuum drying, 1-butyl-3-methyl imidazole salicylic acid ionic liquid is obtained, recorded as [BMIM][SA].

[0062] Put 5.69 g stearic acid and 2.45 g benzoic acid into 80 g 4016 base oil at 90℃, then add 11.37 g titanium isopropyl ester, carry out saponification reaction at 95℃ for 1 h, continue to add 1.09 g deionized water to carry out hydration reaction for 0.5 h, continue to heat the mixed system to 210℃, high temperature refining for 5 min, cool to room temperature, then use three roll mill to grind three times, get the composite titanium base grease, recorded as TCG.

[0063] Take 0.5 g [BMIM] [SA] into 99.5 g TCG, after fully stirring, use three roll mill to grind three times, get the grease containing 0.5% mass fraction of salicylic acid ionic liquid, recorded as TCG+0.5%[BMIM][SA].

[0064] Comparative example 2

[0065] [BMIM][SA], TCG preparation method is same with comparative example 1.

[0066] Take 1 g[BMIM][SA] into 99 g TCG, after stirring evenly, use three roll mill grinding three times, get the grease containing mass fraction 0.5% of salicylic acid ionic liquid, recorded as TCG+0.5%[BMIM][SA].

[0067] Comparative example 3

[0068] [BMIM][SA], TCG preparation method is same with comparative example 1.

[0069] Take 2 g[BMIM][SA] into 98 g TCG, after stirring evenly, use three roll mill grinding three times, get the grease containing mass fraction 0.5% of salicylic acid ionic liquid, recorded as TCG+0.5%[BMIM][SA].

[0070] Performance test of caffeate ionic liquid as grease additive

[0071] Tribological performance test:

[0072] On four ball friction and wear tester, the lubricating performance of caffeate ionic liquid as grease additive was investigated, and compared with base grease (TCG) and [BMIM][SA].

[0073] Select load 392 N, temperature 75 ℃, speed 1200 r / min, experimental time 60 min, the upper and lower test ball used in test is GCr15 bearing steel, its physical parameters are: diameter 12.7mm, hardness HRC 60-63. After friction experiment, optical microscope was used to detect the wear diameter of steel ball. The friction experiment results are shown in table 1.

[0074] Table 1 comparison of average friction coefficient of base grease and ionic liquid-containing grease

[0075]

[0076] From table 1, it can be seen that compared with base grease (TCG) and [BMIM][SA] ionic liquid in comparative examples 1-3, the caffeate ionic liquid of the application has excellent tribological performance.

[0077] Rheological property test:

[0078] MCR302e rotary rheometer of Swiss Anton Paar Company was used to evaluate the storage modulus G' and loss modulus G'' of grease and other parameters, to determine the linear viscoelastic region range and structure strength of grease, and to compare the influence law of caffeate ionic liquid and [BMIM][SA] on structure strength of grease.

[0079] The main technical parameters of the rheometer are as follows: maximum torque 230 mN·m, torque resolution 0.1 nN·m, angular frequency range 10 -7 ~628 rad·s -1 , rotational speed range 10 -9 ~3000 rpm, normal stress range 0.005~50 N. The rheological test experimental parameters are as follows: flat plate rotor PP 25 is selected, in oscillation mode, the temperature is controlled at 25℃, the fixed angular frequency ω is 10 rad·s -1 , and the results are shown in Figure 1 and Figure 2 .

[0080] According to the rheological performance results, compared with the [BMIM][SA] ionic liquid in Comparative Examples 1~3, the ionic liquid of caffeate salt in the application can effectively improve the yield stress and cross stress of the composite titanium-based lubricating grease, and significantly enhance the structural strength of the composite titanium-based lubricating grease.

[0081] In summary, compared with the [BMIM][SA] ionic liquid in Comparative Examples 1~3, the ionic liquid of caffeate salt in the application as an additive of the composite titanium-based lubricating grease shows excellent friction-reducing and anti-wear performance, and can be used as a high-performance friction-reducing and anti-wear additive in the field of lubrication engineering.

Claims

1. A caffeate ionic liquid, characterized by: The structure of the caffeic acid salt ionic liquid is as follows: The R1 group is one of n-hexyl or n-octyl.

2. The method for preparing a caffeate salt ionic liquid as described in claim 1, characterized in that: The caffeic acid and sodium bicarbonate are respectively completely dissolved with anhydrous ethanol and ultrasonic dispersed for 5-10 min, to obtain caffeic acid ethanol solution with a concentration of 0.12 g / ml and sodium bicarbonate ethanol solution with a concentration of 0.17 g / ml; then the sodium bicarbonate ethanol solution is slowly added into the caffeic acid ethanol solution, and the reaction is carried out at normal temperature for 8-12 h under magnetic stirring to obtain a mixed solution; 1,3-dialkyl imidazole chloride is added into the mixed solution, and the reaction is carried out at normal temperature for 24-36 h under magnetic stirring; after the reaction is completed, white solid is precipitated, and the lower liquid is filtered, and then is sequentially subjected to rotary evaporation, washing, purification and vacuum drying to obtain caffeic acid salt ionic liquid; the mass ratio of the sodium bicarbonate to the caffeic acid is 1:2.15; the mass ratio of the 1,3-dialkyl imidazole chloride to the sodium bicarbonate is 1:0.35-0.50; the 1,3-dialkyl imidazole chloride refers to chloride salt of .

3. Use of a coffeeate ionic liquid according to claim 1, characterized in that: The caffeic acid salt ionic liquid and the composite titanium-based grease are uniformly stirred, and then are ground by a three-roll mill for three times to obtain the lubricating grease.

4. Use of a coffeeate ionic liquid according to claim 3, characterized in that: The composite titanium-based grease is prepared by the following method: stearic acid and benzoic acid are dissolved in base oil at 90 DEG C, then isopropyl titanate is added, a saponification reaction is carried out at 95 DEG C for 1 h, deionized water is continuously added to carry out a hydration reaction for 0.5 h, the mixed system is continuously heated to 210 DEG C to carry out a high-temperature refining for 5 min, and then the system is cooled to room temperature and ground by a three-roll mill for three times to obtain the composite titanium-based grease.

5. Use of a caffeate ionic liquid according to claim 4, characterized in that: The mass ratio of the stearic acid, the benzoic acid, the base oil, the isopropyl titanate and the deionized water is 1:0.43:14.06:2:0.

2.

6. Use of a coffeeate ionic liquid according to claim 3, characterized in that: The mass fraction of the caffeic acid salt ionic liquid in the lubricating grease is 0.5-2%.

Images