Rigid spiro compound as well as preparation method and application thereof

Abstract

The invention relates to a rigid spiro compound and a preparation method and application thereof.The preparation method comprises the steps that 6-methylene-androstane-4-ene-3, 17-diketone (V) is dissolved in a mixed solution of dichloromethane and trifluoroacetic acid, reaction and reduced pressure distillation are conducted at the temperature of 20-25 DEG C, then extraction washing and distillation are conducted, a rigid spiro compound crude product can be obtained, and the rigid spiro compound is obtained. The crude product can be subjected to column chromatography separation and purification to obtain a refined rigid spiro compound (I). By adopting the preparation method, the friction and wear properties of the base oil are remarkably improved, and the base oil has lower friction coefficient and wear scar diameter, and has good application prospect as an antifriction and wear-resistant additive.

Description

Technical Field

[0001] The present invention relates to a method for preparing a rigid spirocyclic compound and its application as a lubricating oil additive, belonging to the technical field of lubricating oil additive application Background Art

[0002] About 1 / 3 of the energy consumption of mechanical equipment is generated by friction, which not only leads to huge waste of resources, but also causes wear and failure of parts. Lubrication is an important means to solve the friction and wear of moving parts. It can form a lubricating isolation film on the contact surface of moving parts, reduce friction and wear, and improve the working efficiency and service life of parts. Using rigid organic compounds as lubricant additives can significantly improve the anti-wear, friction reduction and extreme pressure properties of base lubricants.

[0003] Due to the particularity and harshness of the service environment of moving parts, the contact surface often needs to withstand large loads, temperatures, pressures and other conditions. These contact conditions have a great influence on the physical properties of the lubricating medium, and it is difficult to stably adsorb on the contact surface for a long time with high reliability, which accelerates the wear of the friction pair surface, increases the surface roughness, and increases the friction coefficient. Therefore, a variety of different types of additives are often added to the base oil to improve its friction reduction, wear resistance and load-bearing properties. Rigid organic compounds, as a typical type of lubricant additive, can significantly improve the anti-wear, friction reduction and extreme pressure properties of the base lubricant.

[0004] Compared with inorganic compound molecules as additives, organic compounds can improve the physical properties and lubricating effect of lubricating oils, and can also adsorb certain solid pollution particles in lubricating oils, float on the surface of lubricating oils, play a self-cleaning role, improve the lubricating performance of lubricating oils, and extend the service life of moving parts. However, due to the different physical and chemical properties of different base oils, such as ester oils generally have functional groups such as carbonyl oxygen and alcohol oxygen, which give them a certain polarity, while mineral oil molecules are only connected by weak chemical bonds, and decomposition occurs during the friction process. Therefore, in general, anti-wear and friction-reducing additives and extrusion additives suitable for polar ester oils are not suitable for non-polar mineral oils. Therefore, it is proposed to design a rigid spiro compound to adapt to polar ester oils, and by regulating its structure, to improve the adsorption capacity of the metal friction pair surface, thereby improving its friction and wear performance. The target spiro compound is highly anticipated because of its stable rigid structure and good thermal stability. CN106928303B reports a method for preparing a spiro compound, and its preparation process can be expressed as:

[0005]

[0006] However, the inventors have discovered through research that the central spiro carbon position of the target spiro compound is not unique, and the spiro carbon configuration is not unique (there are R or S types), which has an impact on its application. Summary of the invention

[0007] The purpose of the present invention is to overcome the existing technical difficulties and provide a rigid spiro compound for lubricating grease. The rigid spiro compound is prepared from 6-methylene-androst-4-ene-3,17-dione under the action of trifluoroacetic acid using dichloromethane as solvent. The preparation method is simple and the process is mature. As a lubricating oil additive, the friction reduction and wear resistance of the lubricating oil can be significantly improved, and the lubricating oil exhibits a lower friction coefficient and wear amount.

[0008] According to the first aspect of the present invention, the present invention further provides a rigid spirocyclic compound, wherein the rigid spirocyclic compound is a dimer of androstenedione, wherein the androstenedione is 4-androsten-3,17-dione (4-AD), and its structural formula is shown in formula (I):

[0009]

[0010] The rigid spiro compound (I) is a chiral S-type of the central carbon of the spiro ring.

[0011] The friction and wear results show that the rigid spiro compound has an obvious friction and wear effect as a friction and wear reducing additive. The standard used in the test is the general standard for lubricating oil testing - four-ball test method.

[0012] According to the second aspect of the present invention, the present invention provides a method for preparing the rigid spiro compound (I), the preparation method comprising dissolving 6-methylene-androst-4-ene-3,17-dione (V) in a mixed solution of dichloromethane and trifluoroacetic acid, reacting at a temperature of 15-30°C, distilling under reduced pressure, then extracting and washing, distilling off the solvent, and separating to obtain the rigid spiro compound (I). The above reaction process can be expressed as:

[0013]

[0014] In the preferred technical scheme of the preparation method of the present invention, preferably, the amount of dichloromethane used in the reaction is 2400-3600 ml / mol 6-methylene-androst-4-ene-3,17-dione. More preferably, the amount of dichloromethane used is 2700-3300 ml / mol 6-methylene-androst-4-ene-3,17-dione.

[0015] In the preferred technical scheme of the preparation method of the present invention, preferably, the amount of trifluoroacetic acid used in the reaction is 400-600 ml / mol 6-methylene-androst-4-ene-3,17-dione. More preferably, the amount of trifluoroacetic acid used is 450-550 ml / mol 6-methylene-androst-4-ene-3,17-dione.

[0016] In the preferred technical solution of the preparation method of the present invention, preferably, the reaction temperature is 20-25°C.

[0017] In the preferred technical solution of the preparation method of the present invention, preferably, the reaction time is 32 hours.

[0018] According to the third aspect of the present invention, the present invention provides an application of the rigid spiro compound (I) in the preparation of a lubricating oil additive or a lubricating oil friction reducer and wear resistant agent, wherein the rigid spiro compound is used as a lubricating oil additive, a friction reducer and wear resistant agent, and an anti-corrosion additive.

[0019] In the preferred technical solution of the application of the present invention, preferably, the rigid spirocyclic compound is added in an amount of 0.2 wt% to 10 wt% in the lubricating oil, wherein the base oil may be lubricating oil.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1) The rigid spiro compound of the present invention can be dispersed in lubricating oil, and has a huge application space in the field of lubricating oil additives. It can be used as a lubricating oil friction-reducing and wear-resistant additive or anti-wear agent in lubricating grease. The present invention uses dichloromethane as a solvent, and under the action of trifluoroacetic acid, a rigid spiro compound is prepared from 6-methylene-androst-4-ene-3,17-dione, and the excellent structural stability and rigidity of the spiro compound are used to improve the load-bearing capacity of the lubricating grease on the friction contact surface. 2) The method for preparing the rigid spiro compound used in the present invention has many characteristics such as simple operation, mature process, and suitability for mass production. The experimental operation involved in the present invention is simple, the process is reliable, and the prepared rigid spiro compound can play a good friction-reducing and wear-resistant effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the NMR (hydrogen spectrum) of the product prepared under the conditions of Example 1 of the present application;

[0022] Figure 2 This is a single crystal derivative diagram of the product prepared under the conditions of Example 1 of the present application;

[0023] Figure 3 This is a comparison chart of the average friction coefficients of PAO6 base oil and PAO6+0.05% spiro compound under the conditions of Example 1 of the present application;

[0024] Figure 4 This is a comparison chart of the wear spot sizes of PAO6 base oil and PAO6+0.05% spiro compound under the conditions of Example 1 of the present application. DETAILED DESCRIPTION

[0025] The specific implementation modes of the present invention will be further described below in conjunction with examples. It should be noted that certain improvements and optimizations may be made without departing from the principles and purpose of the present invention, and these improvements and optimizations are also within the scope of protection of the present invention.

[0026] In this embodiment, the analytical instruments and equipment used are: liquid chromatography-mass spectrometry, ThermoLCQ-Fleet, column: Hypersil GOLD150*2.1, electrospray ionization source (ESI); nuclear magnetic resonance instrument, AVANCEDMXⅡⅠ400M (TMS internal standard, Bruker); high performance liquid chromatograph: Agilent Technologies 1200 Series; infrared spectrometer, NICOLET360 FT-IR (Nicolet Instruments, USA).

[0027] In this embodiment, the raw materials used can be directly purchased or obtained by simple processing. Among them, the preparation method of the raw material 6-methylene-androst-4-ene-3,17-dione (V) can refer to the patent of Cao Ruiwei et al. (CN105017370).

[0028] Example 1: Preparation of Rigid Spiro Compound (I)

[0029] Mix 300 ml of dichloromethane and 50 ml of trifluoroacetic acid, and control the temperature at 20-25°C. Add 29.85 g of compound V (0.1 mol) and stir the reaction at 20-25°C for 32 hours. Distill off most of the trifluoroacetic acid under reduced pressure. Add 500 ml of dichloromethane and 500 ml of water, stir and separate. Wash the organic layer three times with deionized water. Concentrate the organic layer to dryness to obtain 28.6 g of crude product. The crude product can be separated and purified by column chromatography (eluent: ethyl acetate: petroleum ether = 1:2) to obtain 18.8 g of fine spirocyclic compound (Ⅰ), with a yield of 63%.

[0030] For product structure characterization, please refer to Figure 1 The NMR (hydrogen spectrum) and Figure 2 This is a single crystal derivative diagram of the product prepared under the conditions of Example 1 of this application. Figure 2 , the four groups connected to the central spiro ring carbon are arranged in order and in order as follows: C(005)>C(008)>C(00D)>C(00B), the smallest group, C(00B), is placed farthest from the eye, and the other three groups are rotated from large to small. The rotation direction is counterclockwise, so the central spiro ring carbon is in S configuration.

[0031] Example 2: Preparation of Rigid Spiro Compound (I) by Reaction under Different Conditions

[0032] According to the orthogonal test in Table 1, 29.85 g of 6-methylene-androst-4-ene-3,17-dione (compound V, 0.1 mol), dichloromethane, and trifluoroacetic acid were added to a 1000 ml four-necked reaction bottle in sequence, and the reaction was stirred at a certain temperature. The reaction was detected by thin layer chromatography until the end, and then the low boiling point was recovered under reduced pressure, extracted and washed with dichloromethane-water, and concentrated to dryness to obtain a crude product. The crude product was purified by silica gel column chromatography (eluent: ethyl acetate: petroleum ether = 1:2), and the rigid spiro compound (I) was weighed, and the yield was calculated. The results are shown in Table 1.

[0033] In this embodiment, the preparation conditions mainly include three factors: the amount of dichloromethane, the amount of trifluoroacetic acid and the reaction temperature, and a three-factor four-level orthogonal experiment is designed.

[0034] Table 1 Product yields under different preparation conditions

[0035] Serial number Dichloromethane amount (mL) Amount of trifluoroacetic acid (mL) Reaction temperature (℃) Yield (%) 1 200 30 10-15 32.7 2 200 40 20-25 43.9 3 200 50 30-35 42.9 4 200 70 40-45 28.6 5 300 30 20-25 44.1 6 300 40 10-15 54.2 7 300 50 40-45 37.1 8 300 70 30-35 47.2 9 400 30 30-35 42.8 10 400 40 40-45 27.8 11 400 50 10-15 59.3 12 400 70 20-25 46.3 13 500 30 40-45 25.5 14 500 40 30-35 47.0 15 500 50 20-25 56.7 16 500 70 10-15 43.2

[0036] The NMR data of the products obtained under the conditions corresponding to the serial numbers in Table 1 are the same as those in Example 1. Comprehensive consideration of the yield, material ratio, and synthesis conditions in Table 1 shows that:

[0037] (1) Influence of solvent usage: This application uses dichloromethane as a solvent, which will directly affect the reaction efficiency and reaction rate of the product. The amount of dichloromethane used was tested through an orthogonal experiment. The results show that when the amount of dichloromethane used is less than 2400 ml / mol 6-methylene-androst-4-ene-3,17-dione, the amount of solvent is too low, resulting in insufficient dissolution of the intermediate, which cannot meet the needs of the reaction, and thus the yield is low (see sequence numbers 1 and 4 in Table 1 for details); as the amount of dichloromethane used increases, when its usage exceeds 2400 ml / mol 6-methylene-androst-4-ene-3,17-dione, the reaction gradually becomes sufficient, especially when the amount of dichloromethane used is between 2400-3600 ml / mol When 6-methylene-androst-4-ene-3,17-dione is used, since the raw materials such as 6-methylene-androst-4-ene-3,17-dione can be fully dissolved, and the dissolved raw materials such as 6-methylene-androst-4-ene-3,17-dione can meet the reaction requirements, the reaction can be fully carried out, the stability of the product is gradually increased, the product quality is good, and the yield can reach 54.2% (see sequence numbers 6 and 8 in Table 1 for details); although the amount of dichloromethane used is further increased, the complete dissolution of 6-methylene-androst-4-ene-3,17-dione is ensured, when the amount of dichloromethane used is greater than 3600 ml / mol 6-methylene-androst-4-ene-3,17-dione, due to the decrease in raw material concentration, the reaction rate is slowed down, resulting in a prolonged reaction time, an increase in side reactions, and a decrease in yield (see sequence numbers 10 and 13 in Table 1 for details). Therefore, the amount of dichloromethane used is appropriately controlled at 2400-3600 mL / mol 6-methylene-androst-4-ene-3,17-dione, and especially when the amount of dichloromethane used is controlled at 2700-3300 mL / mol 6-methylene-androst-4-ene-3,17-dione, the reaction efficiency is optimal.

[0038] (2) Effect of the amount of trifluoroacetic acid used: In the synthesis process of rigid spiro compounds, trifluoroacetic acid is one of the reaction raw materials. The amount of trifluoroacetic acid used was tested through orthogonal experiments. The results showed that when the amount of trifluoroacetic acid used was less than 400 ml / mol 6-methylene-androst-4-ene-3,17-dione, the reaction was incomplete due to insufficient acid and the yield was low (see numbers 1 and 13 in Table 1 for details); as the amount of trifluoroacetic acid used increased, when its addition amount exceeded 400 ml / mol raw material, the reaction gradually became complete, especially when the amount of trifluoroacetic acid added was between 450-550 ml / mol 6-methylene-androst-4-ene-3,17-dione, the yield was good (see numbers 11 and 15 in Table 1 for details); if the amount of trifluoroacetic acid used continued to increase, the excess trifluoroacetic acid would lead to an increase in impurities, a decrease in yield, and was not conducive to the normal progress of the reaction (see numbers 4 and 16 in Table 1 for details). Therefore, the amount of trifluoroacetic acid used is appropriately controlled at 400-600 ml / mol 6-methylene-androst-4-ene-3,17-dione, and in particular, when the amount of trifluoroacetic acid used is controlled at 450-550 ml / mol 6-methylene-androst-4-ene-3,17-dione, the reaction efficiency is optimal.

[0039] (3) Effect of reaction temperature: During the reaction, the reaction temperature will affect the reaction selectivity and conversion rate. The reaction temperature was tested by orthogonal experiment. The results show that when the reaction temperature is lower than 15°C, the reaction time is greatly prolonged due to the slow reaction rate, which in turn leads to an increase in competitive side reactions, and ultimately leads to a low yield (see No. 1 and 16 in Table 1 for details); as the reaction temperature increases, when it exceeds 20°C, the reaction gradually tends to be stable, especially when the reaction temperature is between 20-25°C, the yield is relatively high (see No. 15 in Table 1 for details); continuing to increase the reaction temperature will accelerate the reaction rate, but at the same time it will lead to a significant increase in side reactions, which in turn leads to a low yield (see No. 4 and 13 in Table 1 for details). Therefore, the reaction temperature is preferably controlled at 15-30°C, especially when the reaction temperature is controlled at 20-25°C, the reaction yield is optimal.

[0040] Example 3: Application of rigid spiro compound (I) in the field of lubricating oil

[0041] The spirocyclic compound (I) powder prepared in this example was ultrasonically dispersed as a nano-additive into PAO6 base oil (a low-viscosity polyalphaolefin produced by ExxonMobil Corporation) to prepare a lubricating oil mixture with an additive content of 0.05 wt % (i.e., a mixed oil containing 0.05 wt % of the spirocyclic compound (I), hereinafter referred to as mixed oil PAO6). The tribological behavior was characterized using a four-ball friction and wear tester under the test conditions of 75° C., 392 N, and 1200 r / min. As shown in FIG. Figure 3, as shown in 4.

[0042] Figure 3 The average friction coefficients of base oil PAO6 and blended oil PAO6 obtained under the above test conditions are given. Figure 3 It can be seen that the average friction coefficient of the PAO6 base oil is 0.082, and the average friction coefficient of the mixed oil PAO6 after adding the spiro compound (I) is reduced to 0.063, and the friction coefficient reduction reaches 23.17%. Therefore, the mixed oil PAO6 with the addition of the spiro compound (I) shows a good friction reduction effect.

[0043] Figure 4 Comparison of the wear spot size of base oil PAO6 and blended oil PAO6 (containing 0.05 wt% spiro compound (I)). Figure 4 It can be seen that the mixed oil PAO6 with the addition of the rigid spiro compound (I) exhibits better wear resistance. Under the test conditions of 75°C, 392N, 1200r / min, and 60min of friction, the average wear spot diameter of the base oil PAO6 is 0.817mm, while the average wear spot diameter of the mixed oil PAO6 (containing 0.05wt% spiro compound (I)) is 0.566mm, and the wear resistance is improved by 30.72%, showing a good anti-wear effect.

[0044] In summary, it can be seen that the spirocyclic compound (I) prepared in the present invention has a stable structure, good dispersibility and stability in PAO6 base oil, and exhibits excellent friction reduction and wear resistance. Therefore, it has a good application prospect in the field of lubricating oil additives.

[0045] The above content is a further detailed description of the technical solution provided in combination with the preferred implementation mode of the present invention. It cannot be determined that the specific implementation of the present invention is limited to the above descriptions. For ordinary technicians in the technical field to which the present invention belongs, they can make several simple deductions or substitutions without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A rigid spirocyclic compound, wherein the rigid spirocyclic compound is a dimer of androstenedione, wherein the androstenedione is 4-androsten-3,17-dione (4-AD), and the structural formula thereof is shown in formula (I): The rigid spiro compound (I) is a chiral S-type of the central carbon of the spiro ring.

2. A method for preparing the rigid spiro compound according to claim 1, characterized in that: 6-methylene-androst-4-ene-3,17-dione (V) is dissolved in a mixed solution of dichloromethane and trifluoroacetic acid, reacted at a temperature of 15-30° C., distilled under reduced pressure, then extracted and washed, and the solvent is evaporated to separate and obtain a rigid spiro compound (I).

3. The preparation method according to claim 2, characterized in that: The solvent is dichloromethane, and the amount of dichloromethane used in the reaction is 2400-3600 ml / mol 6-methylene-androst-4-ene-3,17-dione (V).

4. The preparation method according to claim 3, characterized in that: The amount of dichloromethane used is 2700-3300 ml / mol 6-methylene-androst-4-ene-3,17-dione (V).

5. The preparation method according to claim 2, characterized in that: The amount of trifluoroacetic acid used in the reaction is 400-600 ml / mol 6-methylene-androst-4-ene-3,17-dione (V).

6. The preparation method according to claim 5, characterized in that: The amount of trifluoroacetic acid used is 450-550 ml / mol 6-methylene-androst-4-ene-3,17-dione (V).

7. The preparation method according to claim 2, characterized in that: The reaction temperature is 20-25°C.

8. The preparation method according to claim 2 or 7, characterized in that: The reaction time is 32 hours.

9. Use of the rigid spiro compound according to claim 1 in the preparation of a lubricating oil additive or a lubricating oil friction reducing and wear resistant agent, characterized in that: The rigid spiro compound is used as a lubricating oil additive, a friction reducing and anti-wear agent, and an anti-corrosion additive.

10. The use according to claim 9, characterized in that: The rigid spiro compound is added in an amount of 0.2 wt% to 10 wt% in the lubricating oil.

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