A phenylamine compound, a preparation method and application thereof, and a composite lubricating oil and application thereof

Abstract

The present application belongs to the technical field of lubricating oil, and particularly relates to a phenylamine compound, a preparation method and application thereof, a composite lubricating oil and application thereof. The phenylamine compound provided by the present application is organically combined with a shielding phenol, an alkyl aniline and an alkyl phosphite, and can more effectively capture free radicals when the free radicals appear in oil, and exhibits more excellent antioxidant performance. Meanwhile, the phenylamine compound provided by the present application can be used in a working condition of more than 150 DEG C, expands the applicable temperature range when used as an antioxidant, and presents a new mode of "ladder" type antioxidant. The N, P and O elements contained in the phenylamine compound provided by the present application are surface-absorbed or friction chemically reacted with a friction pair, so that the effect of friction reduction and wear resistance is realized. The phenylamine compound provided by the present application has excellent solubility in common base oil, especially non-polar hydrocarbon oil, and simultaneously exhibits excellent antioxidant performance, corrosion resistance and tribological performance under normal temperature and high temperature conditions.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil technology, specifically relating to a phenolic amine compound and its preparation method and application, and composite lubricating oil and its application. Background Technology

[0002] Antioxidants are an indispensable class of additives in lubricant formulations, used to prevent the formation of harmful substances and extend the service life of lubricants. Hindered phenols, as hindered phenolic antioxidants, have been extensively studied for their effectiveness in enhancing the oxidative stability of lubricants. Furthermore, since friction reduction and anti-wear properties are fundamental properties of lubricants, various novel shielded phenolic multifunctional lubricant additives containing active elements (B, N, S, or P) have been developed to impart longer service life and unique lubricating properties to lubricants.

[0003] However, most existing phenol-based multifunctional lubricating oil additives exhibit poor solubility or lubrication performance in non-polar hydrocarbon oils. Therefore, developing novel, efficient, and oil-soluble functional antioxidant systems remains a key research direction. Summary of the Invention

[0004] In view of this, the present invention provides a phenolic amine compound, its preparation method and application, and a composite lubricating oil and its application. The phenolic amine compound provided by the present invention has good solubility in non-polar hydrocarbon oils, and when added as an antioxidant, it can give the lubricant a longer service life and unique lubrication performance.

[0005] To solve the above-mentioned technical problems, the present invention provides a phenolic amine compound having the structure shown in Formula 1: ; Among them, R' and R'' are independently hydrogen, methyl, or tert-butyl, R 1 and R 3 Independently, it can be methyl, ethyl, or n-butyl, R 2 It is a C6-C20 alkyl group, R 4 For hydrogen or hydroxyl, R 5 For hydrogen or hydroxyl, R 4 and R 5 It is neither simultaneously a hydroxyl group nor simultaneously hydrogen.

[0006] Preferably, R' and R'' are the same substituents, R 1 and R 3 For the same substituents, R 2 It is a C8-C12 alkyl group.

[0007] Preferably, the phenolic amine compound has the structure shown in P1-1, P1-2, P1-3 or P2: , , , .

[0008] This invention also provides a method for preparing the phenolic amine compounds described in the above technical solution, comprising the following steps: An aldehyde compound, an aniline compound, an alkyl phosphite ester, and an organic solvent are mixed and then a catalyst is added to carry out a dehydration condensation reaction to obtain the phenolic amine compound. The aldehyde compound is or The aniline compound is The alkyl phosphite is .

[0009] Preferably, the molar ratio of the aldehyde compound to the aniline compound is 1:1 to 3, and the molar ratio of the aldehyde compound to the alkyl phosphite is 1:1 to 3. The catalyst includes p-toluenesulfonic acid, formic acid, or acetic acid; The organic solvent includes one or more of methanol, ethanol, toluene, and xylene.

[0010] Preferably, the dehydration condensation reaction is carried out at a temperature of 40~110℃ for a time of 12~72h.

[0011] The present invention also provides the application of the phenolic amine compounds described in the above technical solutions or the phenolic amine compounds prepared by the preparation methods described in the above technical solutions as antioxidants in lubricating oils.

[0012] The present invention also provides a composite lubricating oil, comprising a base oil and an antioxidant; The antioxidant is a phenolic amine compound as described in the above technical solution or a phenolic amine compound prepared by the preparation method described in the above technical solution.

[0013] Preferably, the base oil includes synthetic ester A51, synthetic ester NP451, base oil PAO2, base oil PAO10, base oil PAO40, base oil 150N, base oil 150SN, base oil 150BS, base oil Yubase6, base oil 500N, or base oil 500SN. The antioxidant content in the composite lubricating oil is 0.5-10% by mass.

[0014] The present invention also provides the application of the composite lubricating oil described above as hydraulic oil, gear oil, and transmission oil.

[0015] This invention provides a phenolic amine compound having the structure shown in Formula 1: Where R' and R'' are independently hydrogen, methyl, or tert-butyl, R1 and R 3 Independently, it can be methyl, ethyl, or n-butyl, R 2 It is a C6-C20 alkyl group, R 4 For hydrogen or hydroxyl, R 5 For hydrogen or hydroxyl, R 4 and R 5 The compounds are neither simultaneously hydroxyl nor simultaneously hydrogen. This invention organically combines shielding phenols, alkylanilines, and alkyl phosphites, resulting in a single molecular structure containing two antioxidants. When free radicals appear in the oil, these compounds can more effectively capture them, exhibiting a synergistic effect and demonstrating superior antioxidant performance. Simultaneously, the phenolic amine compounds provided by this invention can operate at temperatures exceeding 150°C, expanding their applicable temperature range as antioxidants and presenting a novel "stepped" antioxidant model. The N, P, and O elements contained in the phenolic amine compounds provided by this invention undergo surface adsorption or tribochemical reactions with the friction pair, thereby achieving friction reduction and anti-wear effects. The phenolic amine compounds provided by this invention exhibit excellent solubility in common base oils, especially non-polar hydrocarbon oils, and also demonstrate excellent antioxidant properties, corrosion resistance, and tribological properties under both room and high temperature conditions. Attached Figure Description

[0016] Figure 1 The images show copper sheets after corrosion testing. (a) is a blank sample, (b) is the result of soaking in PAO10 base oil, (c) is the result of soaking in PAO10+4wt%P1-1 (Example 5), (d) is the result of soaking in PAO10+4wt%P1-2 (Example 6), (e) is the result of soaking in PAO10+4wt%P1-3 (Example 7), and (f) is the result of soaking in PAO10+4wt%P2 (Example 8). Detailed Implementation

[0017] This invention provides a phenolic amine compound having the structure shown in Formula 1: ; In this invention, R' and R'' are independently hydrogen, methyl, or tert-butyl, and R' and R'' can have the same substituent. Specifically, R' and R'' can simultaneously be tert-butyl, hydrogen, or methyl; R 1 and R 3 Independently, it can be methyl, ethyl, or n-butyl, R 1 and R 3 The same substituents can be used, specifically R 1 and R 3 It can be methyl, ethyl, or n-butyl simultaneously; R 2It is a C6-C20 alkyl group, which can be a C8-C12 alkyl group, and can specifically be octyl or dodecyl; R 4 For hydrogen or hydroxyl, R 5 For hydrogen or hydroxyl, R 4 and R 5 It cannot be hydroxyl at the same time nor hydrogen at the same time; specifically, when R... 4 When it is hydrogen, R 5 For hydroxyl groups, when R 4 When R is a hydroxyl group 5 It is hydrogen.

[0018] In this invention, the phenolic amine compound may have the structure shown in P1-1, P1-2, P1-3 or P2: , , , .

[0019] This invention also provides a method for preparing the phenolic amine compounds described in the above technical solution, comprising the following steps: An aldehyde compound, an aniline compound, an alkyl phosphite ester, and an organic solvent are mixed and then a catalyst is added to carry out a dehydration condensation reaction to obtain the phenolic amine compound. The aldehyde compound is or The aniline compound is The alkyl phosphite is .

[0020] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0021] In this invention, R' and R'' are independently hydrogen, methyl, or tert-butyl, and R' and R'' can have the same substituent. Specifically, R' and R'' can simultaneously be tert-butyl, hydrogen, or methyl. In this invention, the aldehyde compound can specifically be 3,5-di-tert-butylsalicylaldehyde, 3-tert-butyl-2-hydroxybenzaldehyde, 3-tert-butyl-4-hydroxybenzaldehyde, or 3,5-di-tert-butyl-4-hydroxybenzaldehyde.

[0022] In this invention, R 2 It is an alkyl group of C6-C20, which can be an alkyl group of C8-C12, and can be specifically octyl or dodecyl; the aniline compound can be specifically 4-octylaniline or 4-dodecylaniline.

[0023] In this invention, R 1 and R 3 Independently, it can be methyl, ethyl, or n-butyl, R 1 and R 3 The same substituents can be used, specifically R1 and R 3 It can be methyl, ethyl or n-butyl simultaneously; the alkyl phosphite can specifically be diethyl phosphite or dimethyl phosphite.

[0024] In this invention, the molar ratio of the aldehyde compound to the aniline compound can be 1:1 to 3, specifically 1:1.5, 1:2 or 1:2.5; the molar ratio of the aldehyde compound to the alkyl phosphite ester can be 1:1 to 3, specifically 1:1.5, 1:2 or 1:2.5.

[0025] In this invention, the organic solvent may include one or more of methanol, ethanol, toluene, and xylene, specifically methanol, ethanol, toluene, or xylene. In this invention, the molar ratio of the aldehyde compound to the volume of the organic solvent may be 10-100 mmol:100 mL, specifically 15 mmol:100 mL, 20 mmol:100 mL, 30 mmol:100 mL, 50 mmol:100 mL, 70 mmol:100 mL, or 90 mmol:100 mL.

[0026] In this invention, the catalyst may include p-toluenesulfonic acid, formic acid, or acetic acid; the amount of the catalyst used in this invention is not particularly important and can be added according to the conventional amount in the art.

[0027] This invention does not have special requirements for the mixing process, as long as it can be mixed evenly. In this invention, the temperature of the dehydration condensation reaction can be 40~110℃, specifically 50℃, 60℃, 70℃, 80℃, 90℃ or 100℃; the temperature of the dehydration condensation reaction can be provided by an oil bath; the time of the dehydration condensation reaction can be 12~72h, specifically 16h, 20h, 30h, 40h, 48h, 55h, 60h or 70h.

[0028] In this invention, the aldehyde compound is 3,5-di-tert-butyl-4-hydroxybenzaldehyde ( Taking ethanol as an example, the equation for the dehydration condensation reaction is shown in equation a, and the resulting phenolic amine compound is denoted as P1; the aldehyde compound is 3,5-di-tert-butylsalicylaldehyde ( Taking ethanol as an example, the equation for the dehydration condensation reaction is shown in equation b, and the resulting phenolic amine compound is denoted as P2. Formula a; Formula b.

[0029] In this invention, the dehydration condensation reaction may further include: cooling the system after the dehydration condensation reaction to room temperature, removing the solvent by rotary evaporation, and then drying to obtain the phenolic amine compound. In this invention, the room temperature can be 20-35°C, or even 25-30°C; this invention has no special requirements for the cooling method, as long as the desired temperature is reached. In this invention, the drying may include vacuum drying; this invention has no special limitations on the drying conditions, drying to constant weight is sufficient. In this invention, before removing the solvent by rotary evaporation, extraction with dichloromethane may be performed first, the resulting organic phase washed three times with distilled water, and then the solvent removed by rotary evaporation.

[0030] The preparation method provided by this invention is simple and the raw materials are widely available.

[0031] The present invention also provides the application of the phenolic amine compounds described in the above technical solutions or the phenolic amine compounds prepared by the preparation methods described in the above technical solutions as antioxidants in lubricating oils.

[0032] The present invention also provides a composite lubricating oil, comprising a base oil and an antioxidant; wherein the antioxidant is a phenolic amine compound as described in the above technical solution or a phenolic amine compound prepared by the preparation method described in the above technical solution.

[0033] In this invention, the base oil may include synthetic ester A51, synthetic ester NP451, base oil PAO2, base oil PAO10, base oil PAO40, base oil 150N, base oil 150SN, base oil 150BS, base oil Yubase6, base oil 500N, or base oil 500SN; the mass percentage of antioxidant in the composite lubricating oil may be 0.5-10%, specifically 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9%.

[0034] The present invention also provides a method for preparing the composite lubricating oil described in the above technical solution, comprising the following steps: dissolving phenolic amine compounds in a base lubricating oil to obtain the composite lubricating oil.

[0035] In this invention, the melting temperature can be 40~80℃, specifically 40℃, 50℃, 60℃, 70℃ or 80℃.

[0036] The method for preparing composite lubricating oil provided by this invention is simple in process, easy to operate, low in preparation cost, green and environmentally friendly, and suitable for industrial production.

[0037] This invention also provides that the composite lubricating oil described in the above technical solution can be used as hydraulic oil, gear oil, and transmission oil. The composite lubricating oil provided by this invention exhibits excellent oil solubility, friction-reducing and anti-wear properties, lubrication properties, and corrosion resistance at high temperatures.

[0038] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0039] Example 1: Preparation of compound P1-1 In a 250 mL single-necked flask, 3,5-di-tert-butyl-4-hydroxybenzaldehyde (30 mmol, 7.03 g), 4-octylaniline (30 mmol, 6.16 g), diethyl phosphite (30 mmol, 4.14 g), and 100 mL of toluene were added sequentially. The flask was then placed in an 80 °C oil bath and stirred. Two drops of acetic acid catalyst were added, and the mixture was condensed using a condenser. The reaction was allowed to proceed for 48 h. After the reaction time was complete, the reaction mixture was cooled to room temperature (25 °C), extracted with dichloromethane, washed three times with distilled water, the solvent was removed by rotary evaporation, and the mixture was dried under vacuum to obtain compound P1-1 (12.85 g, 74% yield).

[0040] Compound P1-1 1 H NMR (500 MHz, CDCl3- d ) δ 7.21 (d, J = 2.3 Hz, 2H), 6.93 (d, J = 8.4 Hz, 2H), 6.57 (d, J = 8.3 Hz, 2H), 5.18 (s, 1H), 4.22 – 3.99 (m, 4H), 3.88 (dp, J = 10.3, 6.9 Hz, 1H), 3.60 (dp, J = 10.2, 7.1 Hz, 1H), 2.44 (t, J = 7.7Hz, 2H), 1.51 (t, J = 7.6 Hz, 2H), 1.35 (t, J = 7.1 Hz, 21H), 1.28 – 1.20 (m, 12H), 1.04 (t, J = 7.1 Hz, 3H), 0.85 (t, J = 6.8 Hz, 3H).

[0041] Example 2 Preparation of compound P1-2 In a 250 mL single-necked flask, 3,5-di-tert-butyl-4-hydroxybenzaldehyde (30 mmol, 7.03 g), 4-dodecylaniline (30 mmol, 7.84 g), diethyl phosphate (30 mmol, 4.14 g), and 100 mL of toluene were added sequentially. The flask was then placed in an 80 °C oil bath and stirred. Two drops of acetic acid were added as a catalyst, and the mixture was condensed using a condenser. The reaction was allowed to proceed for 48 h. After the reaction time was complete, the reaction mixture was cooled to room temperature (25 °C), extracted with dichloromethane, washed three times with distilled water, the solvent was removed by rotary evaporation, and the mixture was dried under vacuum to obtain compound P1-2 (14.78 g, 80% yield).

[0042] Compound P1-2 1 H NMR (500 MHz, CDCl3- d ) δ 7.25 (d, J = 2.8 Hz, 2H), 6.95 (d, J = 8.0 Hz, 2H), 6.58 (d, J = 8.5 Hz, 2H), 5.20 (s, 1H), 4.23 – 3.99 (m, 4H), 3.87 (dp, J = 10.0, 6.9 Hz, 1H), 3.62 (dp, J = 11.0, 7.1 Hz, 1H), 2.41 (t, J = 7.8Hz, 2H), 1.53 (t, J = 7.4 Hz, 2H), 1.35 (t, J = 7.4 Hz, 21H), 1.29 – 1.18 (m, 20H), 1.05 (t, J = 7.2 Hz, 3H), 0.87 (t, J = 6.8 Hz, 3H).

[0043] Example 3 Preparation of compound P1-3 In a 250 mL single-necked flask, 3,5-di-tert-butyl-4-hydroxybenzaldehyde (30 mmol, 7.03 g), 4-octylaniline (30 mmol, 6.16 g), dimethyl phosphite (30 mmol, 2.88 g), and 100 mL of toluene were added sequentially. The flask was then placed in an 80 °C oil bath and stirred. Two drops of acetic acid were added as a catalyst, and the mixture was condensed using a condenser. The reaction was allowed to proceed for 48 h. After the reaction time was complete, the reaction mixture was cooled to room temperature (25 °C), extracted with dichloromethane, washed three times with distilled water, the solvent was removed by rotary evaporation, and the mixture was dried under vacuum to obtain compound P1-3 (11.96 g, 75% yield).

[0044] Compound P1-3 1 H NMR (500 MHz, CDCl3- d ) δ 7.20 (d, J = 2.0 Hz, 2H), 6.98 (d, J = 9.0 Hz, 2H), 6.55 (d, J = 8.4 Hz, 2H), 5.19 (s, 1H), 4.21 – 3.98 (m, 4H), 3.87 (dp, J = 10.8, 6.8 Hz, 1H), 3.62 (dp, J = 10.7, 7.3 Hz, 1H), 2.41 (t, J = 7.8Hz, 2H), 1.52 (t, J = 7.5 Hz, 2H), 1.32 (t, J = 7.0 Hz, 18H), 1.27 – 1.21 (m, 12H), 1.08 (t, J = 7.4 Hz, 3H), 0.86 (t, J = 7.0 Hz, 3H).

[0045] Example 4: Preparation of compound P2 In a 250 mL single-necked flask, 3,5-di-tert-butylsalicylaldehyde (30 mmol, 7.03 g), 4-octylaminoaniline (30 mmol, 6.16 g), diethyl phosphite (30 mmol, 4.14 g), and 100 mL of toluene were added sequentially. The flask was then placed in an 80 °C oil bath and stirred. Two drops of acetic acid catalyst were added, and the mixture was condensed using a condenser. The reaction was allowed to proceed for 48 h. After the reaction time was complete, the reaction mixture was cooled to room temperature (25 °C), extracted with dichloromethane, washed three times with distilled water, the solvent was removed by rotary evaporation, and the mixture was dried under vacuum to obtain compound P2 (12.34 g, 71% yield).

[0046] Compound P2 1 H NMR (500 MHz, CDCl3- d ) δ 7.32 (s, 1H), 7.12 (s, 1H), 6.56(d, J = 8.2 Hz, 2H), 6.52 (d, J = 8.0 Hz, 2H), 5.24 (s, 1H), 4.29 – 4.00 (m, 4H), 3.80 (dp, J = 9.5, 7.0 Hz, 1H), 3.65 (dp, J = 10.0, 7.4 Hz, 1H), 2.43 (t, J = 6.8 Hz, 2H), 1.50 (t, J = 8.0 Hz, 2H), 1.32 (t, J = 8.0 Hz, 21H), 1.32 – 1.20 (m, 12H), 1.11(t, J = 7.5 Hz, 3H), 0.85 (t, J = 7.0 Hz, 3H).

[0047] Example 5: Preparation of Composite Lubricating Oil A certain mass of compound P1-1 (Example 1) was taken and dissolved in base oil PAO10 at a temperature of 80°C to obtain a composite lubricating oil. The mass percentage of compound P1-1 in the composite lubricating oil was 0, 1, 2, 3, 4 wt%.

[0048] Example 6 The composite lubricating oil was prepared according to the method of Example 5, except that compound P1-1 was replaced with P1-2 prepared in Example 2.

[0049] Example 7 The composite lubricating oil was prepared according to the method of Example 5, except that compound P1-1 was replaced with P1-3 prepared in Example 3.

[0050] Example 8 The composite lubricating oil was prepared according to the method of Example 5, except that compound P1-1 was replaced with P2 prepared in Example 4.

[0051] Comparative Example 1 Commercially available shielding phenolic antioxidant ST135 and aniline antioxidant ST57 are heated and dissolved in base oil PAO10 to obtain a composite lubricating oil containing 2 wt% ST135 and 2 wt% ST57.

[0052] Comparative Example 2 A certain mass of commercially available shielding phenolic antioxidant ST135 was heated and dissolved in base oil PAO10 to obtain a composite lubricating oil containing 4 wt% ST135.

[0053] Test Example 1: Antioxidant Test The antioxidant properties of the composite lubricating oils prepared in Examples 5-8 with different concentrations of additives (phenolic amine compounds) and the composite lubricating oil prepared in Comparative Example 1 were evaluated using a PDSC pressure-tracking differential scanning calorimeter. The experiments were conducted at 180℃ and 3.5 MPa high-purity oxygen. Data on the oxidation induction period were obtained through data acquisition. The test results are shown in Table 1.

[0054] Table 1. Oxidation induction period of the composite lubricating oils prepared in Examples 5-8

[0055] As shown in Table 1, the phenolic amine compounds provided by this invention exhibit excellent antioxidant properties and good oxidation stability at high temperatures. Adding them as antioxidants to base oils can prevent lubrication failure caused by oxidation of the composite lubricating oil under high-temperature conditions. Furthermore, compared to Comparative Example 1, the organic combination of shielding phenol and aniline demonstrates superior antioxidant performance compared to simply blending the two antioxidants, indicating a synergistic effect between the two intramolecular antioxidant factors.

[0056] Test Example 2: Tribological Property Test The tribological properties of the composite lubricating oils containing different mass concentrations of additives prepared in Examples 5-8 and the composite lubricating oil prepared in Comparative Example 2 were tested using an SRV-V reciprocating vibration friction and wear tester. The friction pair of the SRV-V friction and wear tester was in point contact, and both upper and lower samples were made of AISI 52100 bearing steel with an average hardness of 748.45 HV. The upper sample steel ball (diameter: 10 mm) and the lower sample circular steel disc (diameter: 24 mm, height: 7.9 mm) were thoroughly cleaned with ethanol and fixed in the test area of ​​the SRV-V. The composite lubricating oils prepared in Examples 5-8 and Comparative Example 2 were dripped into the contact area of ​​the upper and lower samples and tested continuously for 30 min with a load of 300 N or 200 N, a frequency of 25 Hz, and an amplitude of 1 mm (relative humidity: 40-50%, temperature: 25℃ or 100℃). The friction coefficient curve was obtained through the data acquisition system, and the average friction coefficient was obtained. After the friction and wear test, the three-dimensional morphology and wear volume of the wear track were obtained by scanning with a Bruker optical profilometer. The test results are shown in Tables 2 and 3.

[0057] Table 2. Tribological properties of compounds in composite lubricating oils at room temperature (25℃)

[0058] Table 3. Tribological properties of compounds in composite lubricating oils at high temperatures (100℃)

[0059] As can be seen from Tables 2-3, the phenolic amine compounds provided by this invention have excellent friction-reducing and anti-wear properties under both room temperature and high temperature conditions. Compared with Comparative Example 2, the friction-reducing and anti-wear effects are significantly improved, which fully demonstrates that introducing the phenolic amine compounds provided by this invention into N and P and adding them to lubricating oil as antioxidants can improve its tribological properties.

[0060] Test Example 3 Corrosion Resistance Test The composite lubricating oil containing 4 wt% antioxidant and PAO10 base oil prepared in Examples 5-8 were used as test objects. Copper sheets were immersed in the PAO10 base oil and composite lubricating oil and heated at 150°C for 3 hours. After the heating test, the lubricating oil on the surface of the copper sheet was rinsed off with petroleum ether, the solvent was dried, and the discoloration of the copper sheet was observed to determine the corrosion resistance of the prepared phosphite phenolic compound. The copper sheet photographs after the corrosion test are shown below. Figure 1As shown, (a) is a blank sample (copper sheet without soaking), (b) is the result of soaking in PAO10 base oil, (c) is the result of soaking in PAO10+4wt%P1-1 (Example 5), (d) is the result of soaking in PAO10+4wt%P1-2 (Example 6), (e) is the result of soaking in PAO10+4wt%P1-3 (Example 7), and (f) is the result of soaking in PAO10+4wt%P2 (Example 8).

[0061] Depend on Figure 1 It can be seen that the copper sheet immersed in PAO10 turned magenta, indicating severe corrosion. However, the copper sheet immersed in the composite lubricating oils prepared in Examples 5-8 showed no significant color difference compared to the blank copper sheet, indicating that the phosphite phenolic amine compounds prepared in this invention possess excellent anti-corrosion properties.

[0062] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A phenolic amine compound, characterized in that, It has the structure shown in Equation 1: ； Among them, R' and R'' are independently hydrogen, methyl or tert-butyl, R 1 and R 3 Independently, it can be methyl, ethyl, or n-butyl, R 2 It is a C6-C20 alkyl group, R 4 For hydrogen or hydroxyl, R 5 For hydrogen or hydroxyl, R 4 and R 5 It is neither simultaneously a hydroxyl group nor simultaneously hydrogen.

2. The phenolic amine compound according to claim 1, characterized in that, R' and R'' are the same substituents, R 1 and R 3 For the same substituents, R 2 It is a C8-C12 alkyl group.

3. The phenolic amine compound according to claim 1 or 2, characterized in that, The phenolic amine compounds have the structures shown in P1-1, P1-2, P1-3, or P2: 、 、 、 。 4. A method for preparing the phenolic amine compound according to any one of claims 1 to 3, characterized in that, Includes the following steps: An aldehyde compound, an aniline compound, an alkyl phosphite ester, and an organic solvent are mixed and then a catalyst is added to carry out a dehydration condensation reaction to obtain the phenolic amine compound. The aldehyde compound is or The aniline compound is The alkyl phosphite is .

5. The preparation method according to claim 4, characterized in that, The molar ratio of the aldehyde compound to the aniline compound is 1:1 to 3, and the molar ratio of the aldehyde compound to the alkyl phosphite is 1:1 to 3. The catalyst includes p-toluenesulfonic acid, formic acid, or acetic acid; The organic solvent includes one or more of methanol, ethanol, toluene, and xylene.

6. The preparation method according to claim 4 or 5, characterized in that, The dehydration condensation reaction is carried out at a temperature of 40~110℃ for a time of 12~72h.

7. The use of the phenolic amine compound according to any one of claims 1 to 3 or the phenolic amine compound prepared by the preparation method according to any one of claims 4 to 6 as an antioxidant in lubricating oil.

8. A composite lubricating oil, characterized in that, Includes base oils and antioxidants; The antioxidant is a phenolic amine compound as described in any one of claims 1 to 3 or a phenolic amine compound prepared by the preparation method described in any one of claims 4 to 6.

9. The composite lubricating oil according to claim 8, characterized in that, The base oils include synthetic ester A51, synthetic ester NP451, base oil PAO2, base oil PAO10, base oil PAO40, base oil 150N, base oil 150SN, base oil 150BS, base oil Yubase6, base oil 500N, or base oil 500SN. The antioxidant content in the composite lubricating oil is 0.5-10% by mass.

10. The application of the composite lubricating oil according to claim 8 or 9 as hydraulic oil, gear oil, or transmission oil.

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