An antioxidant and anti-wear dual-function lubricating additive, its preparation method and its application

Abstract

This invention provides a dual-function lubricant additive with antioxidant and anti-wear properties, its preparation method, and its application. The additive is named (3,5-di-tert-butyl-4-hydroxyphenyl)methylphosphonate dibutyl ester, with the following structural formula: [structural formula would be inserted here]. The additive is prepared by reacting 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol and dibutyl phosphite at 80-100°C and a vacuum of 0.080-0.100 MPa for 2-5 hours to obtain a crude product. This crude product is then dissolved in petroleum ether, recrystallized, and dried to obtain the final product. This dual-function lubricant additive exhibits antioxidant properties and excellent anti-wear and friction-reducing properties. It is suitable for use in high-temperature chain oils based on synthetic esters to improve their high-temperature antioxidant and anti-wear properties.

Description

Technical Field

[0001] This invention relates to the field of lubricant additive technology, specifically to an antioxidant and anti-wear dual-function lubricant additive, its preparation method, and its application. Background Technology

[0002] High-temperature chain oil is a fully synthetic, high-performance lubricant that protects and lubricates chains at high temperatures (operating temperatures > 180℃). In addition, it also provides some anti-corrosion, rust prevention, cleaning, and noise reduction properties. High-temperature chain oil is particularly suitable for precision instruments, mechanical parts operating under high-temperature conditions, and heavy-duty, high-load equipment. Its applications are wide-ranging, including textile setting machines, sheet metal production, fiberglass production lines, and automotive paint lines. High-temperature chain oils are typically based on synthetic esters, such as trimellitate and dipentaerythritol esters. However, there are very few anti-wear additives suitable for high-temperature conditions. Tricresol phosphate is commonly used in the industry, but due to its low phosphorus content and inertness, it cannot form an efficient lubricating film between friction pairs during use, leading to increased wear and friction, thus affecting equipment lifespan. Some anti-wear additives with excellent lubrication properties, such as dibutyl phosphite, are difficult to apply in high-temperature (>100℃) environments due to their low decomposition temperature and high reactivity.

[0003] This invention modifies the structure of dibutyl phosphite to prepare a derivative of dibutyl phosphite, significantly improving the thermal stability deficiency of dibutyl phosphite. This dibutyl phosphite derivative can be applied to high-temperature chain oils (operating temperature > 180℃) and exhibits excellent anti-wear properties, showing a significant performance improvement compared to traditional tricresyl phosphate anti-wear agents. Furthermore, this dibutyl phosphite derivative also possesses certain antioxidant properties, making it a dual-functional lubricant additive with both antioxidant and anti-wear functions. Summary of the Invention

[0004] The purpose of this invention is to provide an antioxidant and anti-wear dual-function lubricating additive, its preparation method, and its application. This antioxidant and anti-wear dual-function lubricating additive has excellent high-temperature anti-wear performance in synthetic ester base oils, and at the same time, it has very good antioxidant performance, with an antioxidant effect that is superior to traditional phenolic antioxidants.

[0005] The present invention provides a dual-function lubricant additive with antioxidant and anti-wear properties, which has a simple preparation process and high yield.

[0006] This invention is achieved through the following technical solution:

[0007] An antioxidant and anti-wear dual-function lubricant additive, the structure of which is shown below:

[0008] ;

[0009] (1) (3,5-di-tert-butyl-4-hydroxyphenyl)methylphosphonic acid dibutyl ester.

[0010] A method for preparing the antioxidant and anti-wear dual-function lubricant additive as described above, the method comprising: using 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol and dibutyl phosphite as raw materials, reacting at a temperature of 80-100℃ (e.g., 80℃, 85℃, 90℃, 95℃ or 100℃) and a vacuum degree of 0.080-0.100MPa (e.g., 0.080 MPa, 0.085MPa, 0.090 MPa, 0.095MPa or 0.100MPa) for 2-5 hours (e.g., 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours or 5 hours) to obtain a crude product, dissolving it in petroleum ether, recrystallizing it, and drying it to obtain the final product.

[0011] Specifically, a method for preparing an antioxidant and anti-wear dual-function lubricant additive as described above includes the following steps:

[0012] 2,6-Di-tert-butyl-p-(dimethylaminomethyl)phenol and dibutyl phosphite in a molar ratio of 1:1 were added to a reaction flask and reacted at 90℃ and 0.090 MPa for 3 h to obtain a crude product. Petroleum ether was added and the crude product was completely dissolved at 60℃. After recrystallization at room temperature for 24 h, the final product was obtained by filtration, washing with petroleum ether, and vacuum drying.

[0013] The present invention also provides an application of the antioxidant and anti-wear dual-function lubricating additive as described above, which is used in synthetic ester base oils. The amount of the antioxidant and anti-wear dual-function lubricating additive in the base oil is 0.5 wt% to 2 wt% based on the mass of the base oil. For example, the amount of the antioxidant and anti-wear dual-function lubricating additive in the base oil is 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, or 2 wt% based on the mass of the base oil.

[0014] Technical features and beneficial effects of the present invention:

[0015] This invention discloses an antioxidant and anti-wear dual-function lubricating additive, its preparation method, and its application. The preparation process of this antioxidant and anti-wear dual-function lubricating additive is simple and the yield is high. It exhibits excellent high-temperature anti-wear performance in synthetic ester base oils. At the same time, this antioxidant and anti-wear dual-function lubricating additive has excellent antioxidant properties and has a better antioxidant effect compared with traditional phenolic antioxidants. Attached Figure Description

[0016] Figure 1 The infrared spectrum of the antioxidant and anti-wear dual-function lubricant additive prepared in Example 1 of this invention.

[0017] Figure 2 This is a mass spectrum of the antioxidant and anti-wear dual-function lubricant additive prepared in Example 1 of the present invention.

[0018] Figure 3 The thermogravimetric analysis diagram shows the anti-oxidation and anti-wear dual-function lubricating additive prepared in Example 1 of this invention.

[0019] Figure 4 The graph shows a comparison of the initial oxidation temperatures of oil samples prepared in Example 1 with the addition of 0.5 wt%, 1.0 wt%, and 2.0 wt% of the antioxidant and anti-wear dual-function lubricating additive to the base oil, respectively.

[0020] Figure 5 The images show a comparison of the oxidation induction period at 210℃ for oil samples containing 1.0wt% L135, 1.0wt% L101, and 1.0wt% of the anti-oxidation and anti-wear dual-function lubricating additive prepared in Example 1, respectively.

[0021] Figure 6 The figures show a comparison of the wear marks after friction at different temperatures (a, d), oil samples with 1.0 wt% tricresyl phosphate added (b, e), and oil samples with 1.0 wt% antioxidant and anti-wear dual-function lubricant additive prepared in Example 1 (c, f). Detailed Implementation

[0022] The present invention will be further described and illustrated below with reference to specific embodiments and accompanying drawings.

[0023] Example 1

[0024] 10.52 g (0.04 mol) of 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol and 7.77 g (0.04 mol) of dibutyl phosphite were weighed and added sequentially to a 100 mL three-necked flask. The mixture was reacted at 90 °C and a vacuum of 0.090 MPa for 3 h. After cooling to room temperature, the crude product was obtained. 50 mL of petroleum ether was added and heated to 60 °C. The mixture was stirred until completely dissolved and then cooled to room temperature for recrystallization. After 24 h, the product was filtered to obtain yellow solid particles. The filter was washed three times with petroleum ether and dried in a vacuum oven at 50 °C for 3 h to obtain the final product, weighing 15.4 g, with a yield of 93%.

[0025] Infrared spectroscopy analysis:

[0026] Figure 1The infrared spectrum of the product from Example 1 is shown, with a test range of 600 cm⁻¹. -1 ~4000cm -1 3650cm -1 The absorption peak for phenolic hydroxyl groups is 3200 cm⁻¹. -1 This is the absorption peak after the association of phenolic hydroxyl groups, at 1260 cm⁻¹. -1 The absorption peak is at 1057 cm⁻¹ (P=O). -1 The absorption peak is at 640 cm⁻¹ (POC). -1 The absorption peak is at 2420 cm⁻¹ for PC, while the peak for dibutyl phosphite is at 2420 cm⁻¹. -1 The disappearance of the pH absorption peak indicates that the pH bond in dibutyl phosphite has completely reacted and been converted into a PC bond.

[0027] Mass spectrometry analysis:

[0028] Figure 2 The image shows the mass spectrum (ESI-MS, negative ion mode) of the product from Example 1. The quasi-molecular ion peak at m / z 411.2666 is inferred to be formed by the removal of a hydrogen atom from the parent molecule (3,5-di-tert-butyl-4-hydroxyphenyl)methylphosphonate (molecular weight 412.27). Combined with infrared analysis, this confirms that the product of Example 1 is (3,5-di-tert-butyl-4-hydroxyphenyl)methylphosphonate.

[0029] Thermogravimetric analysis:

[0030] Figure 3 The thermogravimetric curves of the product of Example 1 and dibutyl phosphite are shown. The experimental conditions were: nitrogen as the protective gas, air as the purge gas, both at a flow rate of 80 ml / min, a heating rate of 10 °C / min, and a temperature range of 30 °C to 700 °C. The initial decomposition temperature of the prepared antioxidant and anti-wear dual-function lubricant was 307.7 °C, which is higher than the initial decomposition temperature of dibutyl phosphite (155.1 °C). This indicates that the thermal stability of the prepared antioxidant and anti-wear dual-function lubricant is significantly improved compared to dibutyl phosphite, making it suitable for higher temperature operating conditions.

[0031] To better understand the tribological and antioxidant properties of the prepared anti-oxidation and anti-wear dual-function lubricating additive, the product of Example 1 and commonly used antioxidant or anti-wear additives were added to base oils to obtain lubricating oil samples. The specific implementation schemes are shown in Table 1.

[0032] Table 1 Composition of Examples 2-4 and Comparative Examples 1-4

[0033]

[0034] Note: The viscosity of trimellitate base oil at 40°C is 71.9 mm. 2 / s, viscosity at 100℃ 9.5 mm2 / s; L135 and L101 are phenolic antioxidants produced by BASF; tricresyl phosphate is an anti-wear agent.

[0035] Antioxidant performance test:

[0036] The initial oxidation temperature of Comparative Example 1, Example 2, Example 3, and Example 4 was tested using a PDSC high-pressure differential scanning calorimeter. The test conditions were: oil sample 3 mg ± 0.05 mg, protective gas nitrogen, pressure 3.5 MPa, oxygen flow rate 100 ml / min, and temperature range 30–350 °C. The test results are shown below. Figure 4 .

[0037] from Figure 4 It can be seen that the initial oxidation temperature of Examples 2, 3, and 4 is higher than that of Comparative Example 1. The initial oxidation temperature of the trimellitate base oil is 206.3℃. The initial oxidation temperature of the oil samples with 0.5wt%, 1wt%, and 2wt% of the product of Example 1 increases by 15.7℃, 28.8℃, and 35.9℃ respectively. It can be seen that the prepared antioxidant and anti-wear dual-function lubricating additive has better antioxidant performance than trimellitate base oil.

[0038] Furthermore, the antioxidant properties of the product of Example 1 were compared with those of traditional phenolic antioxidants. The oxidation induction period was tested using a PDSC high-pressure differential scanning calorimeter. The test conditions were: oil sample 3 mg ± 0.05 mg, protective gas nitrogen, pressure 3.5 MPa, oxygen flow rate 100 ml / min, and temperature 210 °C. The test results are shown below. Figure 5 .

[0039] from Figure 5 It can be seen that the oxidation induction period of Comparative Example 2 is 4.7 min; the oxidation induction period of Comparative Example 3 is 6.9 min; and the oxidation induction period of Example 3 is 12.0 min. It is evident that the prepared antioxidant and anti-wear dual-function lubricant additive has better antioxidant performance than traditional phenolic antioxidants.

[0040] Tribological performance testing:

[0041] The testing instrument is SRV- The fretting friction and wear testing machine uses a φ10mm steel ball as the upper friction pair and a φ24×7.9mm steel block as the lower friction pair, both made of GCr15 steel, with point contact. The test conditions are: test load 50N, stroke 1mm, frequency 50Hz, test time 1800s, and test temperatures of 180℃ and 210℃.

[0042] The test oil samples were Comparative Example 1, Comparative Example 4, and Example 3. The test results of their tribological properties are shown in Table 2 and... Figure 6 As shown.

[0043] Table 2. Diameter of the wear scar on the upper friction pair after reciprocating friction tests on three oil samples at different temperatures.

[0044]

[0045] As shown in Table 2, the base oil exhibited the largest wear scar diameters after friction tests at 180℃ and 210℃, at 0.738 mm and 0.772 mm, respectively. The oil sample with the addition of 1.0 wt% tricresyl phosphate showed a 42.1% and 38.9% decrease in wear scar diameter at 180℃ and 210℃, respectively. The oil sample with the addition of 1.0 wt% of the product from Example 1 showed a 50.4% and 54.4% decrease in wear scar diameter at 180℃ and 210℃, respectively. The product from Example 1 demonstrates superior anti-wear performance at high temperatures compared to the traditional anti-wear agent tricresyl phosphate. Figure 6 The surface morphology of the middle and lower friction pairs also shows that the oil sample with 1.0 wt% trimellitate added to the product of Example 1 has better anti-wear performance than the oil sample with 1.0 wt% trimellitate added to the trimellitate, and both have better anti-wear performance than the base oil.

[0046] 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 principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a dual-function lubricating additive with antioxidant and anti-wear properties, characterized in that, The antioxidant and anti-wear dual-function lubricant additive has the structural formula (1): (1)； The method is as follows: 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol and dibutyl phosphite in a molar ratio of 1:1 are added to a reaction flask and reacted at 90℃ and 0.090MPa for 3 hours to obtain a crude product. Petroleum ether is added and the crude product is completely dissolved at 60℃. After cooling to room temperature and recrystallizing for 24 hours, the final product is obtained by filtration, washing with petroleum ether, and vacuum drying. The antioxidant and anti-wear dual-function lubricant additive is added to the base oil at a concentration of 0.5 wt% to 1.9 wt% of the base oil by weight. The base oil is a synthetic ester.

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