Phenolic ester antioxidant, lubricating oil composition as well as preparation and application of phenolic ester antioxidant and lubricating oil composition

Abstract

The invention relates to the field of lubricating oil, in particular to a phenolic ester antioxidant, a lubricating oil composition and preparation and application of the phenolic ester antioxidant and the lubricating oil composition. The preparation method of the phenolic ester antioxidant comprises the following steps: mixing alkylphenol and formaldehyde at 50-55 DEG C under the protection of nitrogen to synthesize a first intermediate; mixing the first intermediate and polyethylene polyamine at 50-55 DEG C under the protection of nitrogen to synthesize a second intermediate; mixing alkylphenol and triethyl phosphite, and synthesizing a third intermediate by taking anhydrous potassium carbonate as a catalyst; and mixing the second intermediate and the third intermediate, and synthesizing the phenolic ester antioxidant by taking anhydrous potassium carbonate as a catalyst. The phenolic ester antioxidant provided by the invention has excellent oxidation resistance and detergency and dispersibility, and can reduce the paint film formation tendency when the lubricating oil is used.

Description

Technical Field

[0001] This application relates to the technical field of lubricating oils, specifically to a phenolic ester antioxidant, a lubricating oil composition, and its preparation and application. Background Technology

[0002] Centrifugal compressors are rotary vane compressors primarily used for gas compression and are key equipment widely used in coal mines, oil fields, and refining plants. To improve efficiency, centrifugal compressors are continuously being developed towards higher speeds and higher compression ratios, leading to a continuous increase in axial force and consequently, higher thrust bearing temperatures. Typically, the operating temperature of centrifugal compressor bearings is 45–50°C, but at high speeds, the bearing temperature can reach over 120°C, and short-term operating temperatures can exceed 150°C. Furthermore, the violent agitation of the oil at high speeds increases the amount of air mixed into the oil, and the bursting of more foam generates even more instantaneous high temperatures. Therefore, at high speeds, the lubricating oil in centrifugal compressors operates under prolonged high temperatures, and localized, short-term ultra-high temperature conditions can lead to rapid lubrication failure.

[0003] Currently, the requirements for high-speed centrifugal compressor lubricating oils are constantly increasing in terms of high-temperature oxidation resistance, anti-varnish formation ability, and rust prevention. Antioxidants are one of the important components of lubricating oils. At present, the improvement of the oxidation resistance of oils is usually reflected in the oxidation induction period increasing several times. However, the oxidation induction period and the ease of varnish formation do not show a positive correlation trend. The tendency to form varnish is still relatively high in centrifugal compressors. Summary of the Invention

[0004] This application aims to provide a phenolic ester antioxidant, a lubricating oil composition, and its preparation and application, to reduce the tendency of varnish formation during the use of lubricating oils. The technical solution adopted in this application is as follows:

[0005] A phenolic ester antioxidant, the structural formula of which is shown in formula (I).

[0006]

[0007] Where x = 1 to 5, n = 12 to 20.

[0008] In a specific implementation, as an option, in equation (I), x = 1 to 2 and n = 12 to 16.

[0009] Secondly, this application also relates to a method for using the aforementioned phenolic ester antioxidants, characterized in that it includes:

[0010] Alkylphenol and formaldehyde were mixed at 50–55°C under nitrogen protection to synthesize the first intermediate.

[0011] The first intermediate and polyethylene polyamine were mixed at 50–55°C under nitrogen protection to synthesize the second intermediate.

[0012] The third intermediate was synthesized by mixing alkylphenol and triethyl phosphite with anhydrous potassium carbonate as a catalyst.

[0013] The second and third intermediates are mixed, and anhydrous potassium carbonate is used as a catalyst to synthesize phenolic ester antioxidants.

[0014] In a specific embodiment, optionally, the mass ratio of the alkylphenol, formaldehyde, and polyethylene polyamine is 1:(2-2.5):(1-1.2);

[0015] The mass ratio of the alkylphenol to the triethyl phosphite is 1:(1-1.1);

[0016] The mass ratio of the second intermediate to the third intermediate is 1:(2 to 2.2).

[0017] Thirdly, this application also relates to the use of the above-mentioned phenolic ester antioxidants in lubricating oil compositions.

[0018] Fourthly, this application relates to a lubricating oil composition comprising the aforementioned phenolic ester antioxidant.

[0019] In a specific embodiment, optionally, the following components are included in parts by weight: 0.05 to 0.3 parts of the phenolic ester antioxidant, 0.2 to 0.5 parts of the compound antioxidant, 0.03 to 0.05 parts of the metal passivator, 0.01 to 0.02 parts of the demulsifier, 0.01 to 0.02 parts of the antifoaming agent, 0.02 to 0.03 parts of the extreme pressure anti-wear agent, 0.03 to 0.05 parts of the rust inhibitor, and 99.2 to 99.4 parts of the base oil.

[0020] In a specific embodiment, optionally, the compound antioxidant includes phenolic antioxidants and / or amine antioxidants.

[0021] In a specific embodiment, optionally, the phenolic antioxidant includes 2,6-di-tert-butyl-p-cresol;

[0022] The amine antioxidants include one or more of the following: octylphenyl-α-naphthylamine, dioctyl diphenylamine, dinonyl diphenylamine, octylbutyl diphenylamine, nonylbutyl diphenylamine, styryloctyl diphenylamine, and α-methylstyryl diphenylamine.

[0023] In a specific embodiment, optionally, the metal passivating agent includes one or more of alkylthiadiazole, methylbenztriazole, and N,N'-disaline propylenediamine;

[0024] The demulsifier includes oil-soluble polyether;

[0025] The extreme pressure anti-wear agent includes one or more of di-n-butyl phosphite, triaryl phosphate, and trialkyl phosphate;

[0026] The antifoaming agent includes one or more of polyacrylate, polymethyl methacrylate, No. 1 composite antifoaming agent and No. 2 composite antifoaming agent;

[0027] The rust inhibitor includes succinic anhydride;

[0028] The base oil comprises polyalphaolefins and pentaerythritol esters.

[0029] Fifthly, this application also relates to the use of the above-mentioned lubricating oil composition in centrifugal compressors.

[0030] In summary, the advantages of this application over the prior art include:

[0031] This application provides a phenolic ester antioxidant and its application in lubricating oil compositions. Dry TOST and DKA oxidation tests demonstrate that when this phenolic ester antioxidant is applied to a lubricating oil composition, it exhibits excellent antioxidant properties and a low tendency to form varnish, reducing sludge formation to less than 30 mg. Furthermore, no significant varnish film formed on the inner wall of the glass bottles tested in the DKA oxidation test. Therefore, it replaces the role of detergents in traditional lubricating oil compositions, exhibiting good detergency and dispersibility.

[0032] When the phenolic ester antioxidants in this application are applied to lubricating oil compositions, they improve other properties of the lubricating oil composition, such as heat resistance and light resistance. Adding these phenolic ester antioxidants can reduce the amount of other antioxidants in the lubricating oil composition to below 0.5%. Furthermore, these phenolic ester antioxidants have the advantage of excellent solubility, enabling them to form good compatibility with other components. Detailed Implementation

[0033] The present application will be described in detail below through specific embodiments and comparative examples:

[0034] The inventors discovered that in the prior art, detergents containing metallic components are typically added to engine oil to improve varnish formation. However, the metallic components in these detergents are prone to leaching when exposed to water. When these metallic components in the detergents leach, it can cause metal corrosion, hydrogen embrittlement, and oxidation of the lubricating oil.

[0035] Based on the above problems, the inventors conducted further research and development, resulting in this invention.

[0036] Example 1

[0037] This embodiment provides a phenolic ester antioxidant, the preparation method of which includes:

[0038] (1) Dodecylphenol and a 37% formaldehyde solution were mixed and reacted at 50°C under nitrogen protection for 0.6 h to synthesize the first intermediate. The structural formula of the first intermediate is shown in formula (I):

[0039]

[0040] In equation (Ⅰ), n = 12.

[0041] (2) Polyethylene polyamine was added to the first intermediate in (1), and the mixture was stirred at 50°C under nitrogen protection for 5 hours to synthesize the second intermediate. The structural formula of the second intermediate is shown in formula (II):

[0042]

[0043] In equation (Ⅱ), x = 1 and n = 12.

[0044] In (1) and (2), the mass ratio of dodecylphenol, formaldehyde and polyethylene polyamine is 1:2:1.

[0045] (3) Dodecylphenol and triethyl phosphite were mixed at a mass ratio of 1:1, and anhydrous potassium carbonate was added as a catalyst. The reaction was carried out for 2 hours to synthesize the third intermediate. The structural formula of the third intermediate is shown in formula (Ⅲ):

[0046]

[0047] In equation (Ⅲ), n = 12.

[0048] (4) The second and third intermediates were mixed at a mass ratio of 1:2, and anhydrous potassium carbonate was added as a catalyst. The mixture was reacted for 2 hours to synthesize phenolic ester antioxidants via transesterification. The structural formula of the phenolic ester antioxidant is shown in formula (Ⅳ).

[0049]

[0050] In equation (Ⅳ), x = 1; n = 12.

[0051] Example 2

[0052] The difference between this embodiment and Example 1 is that in (1) and (2), the reaction temperature is 52°C and the mass ratio of dodecylphenol, formaldehyde and polyethylene polyamine is 1:2.2:1.1; in (3), the mass ratio of dodecylphenol and triethyl phosphite is 1:1.1; and in (4), the mass ratio of the second intermediate and the third intermediate is 1:2.1.

[0053] In Equations I to IV, x = 2; n = 12.

[0054] Example 3

[0055] The difference between the phenolic ester antioxidants in this embodiment and those in Example 1 is that, in (1) and (3), hexadecylphenol is used instead of dodecylphenol; in (1) and (2), the reaction temperature is 55°C; and the mass ratio of hexadecylphenol, formaldehyde and polyethylene polyamine is 1:2.5:1.2; in (4), the mass ratio of the second intermediate and the third intermediate is 1:2.2.

[0056] In this embodiment, in equations I to IV, x = 1; n = 16.

[0057] Example 4

[0058] The difference between the phenolic ester antioxidants in this embodiment and those in Example 1 is that, in (1) and (3), hexadecylphenol is used instead of dodecylphenol, and in Formulas I to IV of this embodiment, x = 2 and n = 16.

[0059] Example 5

[0060] The difference between the phenolic ester antioxidant in this embodiment and that in Example 1 is that in (1) and (3), eicosylphenol is used instead of dodecylphenol, and in Formulas I to IV in this embodiment, x = 5 and n = 20.

[0061] Example 6

[0062] This embodiment provides a lubricating oil composition comprising the following components in parts by weight: 0.05 parts of the phenolic ester antioxidant from Example 1, 0.25 parts of octylbutyldiphenylamine, 0.25 parts of octylphenyl-α-naphthylamine, 0.03 parts of alkylthiadiazole, 0.01 parts of oil-soluble polyether, 0.02 parts of triaryl phosphate, 0.02 parts of polyacrylate, 0.03 parts of succinic anhydride, 10 parts of pentaerythritol ester, and 89.34 parts of polyalphaolefin.

[0063] The method for preparing the lubricating oil composition in this embodiment includes:

[0064] All components are stirred at 60°C for 1-1.5 hours until uniformly mixed to obtain the lubricating oil composition.

[0065] Example 7

[0066] This embodiment provides a lubricating oil composition comprising the following components in parts by weight: 0.1 parts of the phenolic ester antioxidant from Example 2, 0.2 parts of dinonyldiphenylamine, 0.2 parts of octylphenyl-α-naphthylamine, 0.1 parts of 2,6-di-tert-butyl-p-cresol, 0.04 parts of methyltriazole, 0.02 parts of oil-soluble polyether, 0.03 parts of triaryl phosphate, 0.02 parts of No. 1 composite antifoaming agent, 0.05 parts of succinic anhydride, 10 parts of pentaerythritol ester, and 89.24 parts of polyα-olefin.

[0067] The method for preparing the lubricating oil composition in this embodiment includes:

[0068] All components are stirred at 62°C for 1-1.5 hours until uniformly mixed to obtain the lubricating oil composition.

[0069] Example 8

[0070] This embodiment provides a lubricating oil composition comprising the following components in parts by weight: 0.25 parts of the phenolic ester antioxidant from Example 3, 0.15 parts of dinonyldiphenylamine, 0.2 parts of octylphenyl-α-naphthylamine, 0.05 parts of 2,6-di-tert-butyl-p-cresol, 0.04 parts of methyltriazole, 0.02 parts of oil-soluble polyether, 0.02 parts of di-n-butyl phosphite, 0.02 parts of No. 2 composite antifoaming agent, 0.04 parts of succinic anhydride, 10 parts of pentaerythritol ester, and 89.21 parts of polyα-olefin.

[0071] The method for preparing the lubricating oil composition in this embodiment includes:

[0072] All components are stirred at 65°C for 1-1.5 hours until uniformly mixed to obtain the lubricating oil composition.

[0073] Example 9

[0074] This embodiment provides a lubricating oil composition comprising the following components in parts by weight: 0.3 parts of the phenolic ester antioxidant from Example 4, 0.2 parts of dioctyl diphenylamine, 0.1 parts of 2,6-di-tert-butyl-p-cresol, 0.03 parts of N,N'-disaline propylene glycol, 0.01 parts of oil-soluble polyether, 0.02 parts of triaryl phosphate, 0.01 parts of polymethacrylate, 0.05 parts of succinic anhydride, 10 parts of pentaerythritol ester, and 89.28 parts of polyalphaolefin.

[0075] The preparation method of the lubricating oil composition in this embodiment is the same as that in Example 6.

[0076] Example 10

[0077] This embodiment provides a lubricating oil composition comprising the following components in parts by weight: 0.3 parts of the phenolic ester antioxidant from Example 5, 0.1 parts of styryl octyl diphenylamine, 0.1 parts of α-methylstyryl diphenylamine, 0.1 parts of 2,6-di-tert-butyl-p-cresol, 0.03 parts of N,N'-disaline propylene glycol, 0.01 parts of oil-soluble polyether, 0.02 parts of trialkyl phosphate, 0.01 parts of polyacrylate, 0.05 parts of succinic anhydride, 10 parts of pentaerythritol ester, and 89.28 parts of polyalphaolefin.

[0078] The preparation method of the lubricating oil composition in this embodiment is the same as that in Example 6.

[0079] Comparative Example 1

[0080] This comparative example provides a lubricating oil composition comprising the following components in parts by weight: 0.03 parts of the phenolic ester antioxidant from Example 1, 0.2 parts of dioctyl diphenylamine, 0.1 parts of 2,6-di-tert-butyl-p-cresol, 0.03 parts of N,N'-disaline propylene glycol, 0.01 parts of oil-soluble polyether, 0.02 parts of triaryl phosphate, 0.01 parts of polyacrylate, 0.05 parts of succinic anhydride, 10 parts of pentaerythritol ester, and 89.55 parts of polyalphaolefin.

[0081] The preparation method of the lubricating oil composition in this embodiment is the same as that in Example 6.

[0082] Comparative Example 2

[0083] This comparative example provides a lubricating oil composition comprising the following components in parts by weight: 0.5 parts of the phenolic ester antioxidant from Example 1, 0.2 parts of nonylbutyl diphenylamine, 0.1 parts of 2,6-di-tert-butyl-p-cresol, 0.03 parts of N,N'-disaline propylene glycol, 0.01 parts of oil-soluble polyether, 0.02 parts of triaryl phosphate, 0.01 parts of polyacrylate, 0.05 parts of succinic anhydride, 10 parts of pentaerythritol ester, and 89.08 parts of polyalphaolefin.

[0084] Comparative Example 3

[0085] This comparative example provides a lubricating oil composition comprising the following components in parts by weight: 0.25 parts octylbutyldiphenylamine, 0.25 parts octylphenyl-α-naphthylamine, 0.03 parts alkylthiadiazole, 0.01 parts oil-soluble polyether, 0.02 parts triaryl phosphate, 0.02 parts polyacrylate, 0.03 parts succinic anhydride, 10 parts pentaerythritol ester, and 89.39 parts polyα-olefin.

[0086] The preparation method of the lubricating oil composition in this embodiment is the same as that in Example 6.

[0087] Comparative Example 4

[0088] This comparative example provides a lubricating oil composition comprising the following components in parts by weight: 0.2 parts dinonyldiphenylamine, 0.2 parts octylphenyl-α-naphthylamine, 0.1 parts 2,6-di-tert-butyl-p-cresol, 0.04 parts methyltriazole, 0.02 parts oil-soluble polyether, 0.03 parts trialkyl phosphate, 0.02 parts No. 1 composite antifoaming agent, 0.05 parts succinic anhydride, 10 parts pentaerythritol ester, and 89.39 parts polyα-olefin.

[0089] The preparation method of the lubricating oil composition in this embodiment is the same as that in Example 6.

[0090] Comparative Example 5

[0091] This comparative example provides a lubricating oil composition comprising the following components in parts by weight: 0.3 parts octylbutyldiphenylamine, 0.25 parts octylphenyl-α-naphthylamine, 0.03 parts alkylthiadiazole, 0.01 parts oil-soluble polyether, 0.02 parts triaryl phosphate, 0.02 parts polyacrylate, 0.03 parts succinic anhydride, 10 parts pentaerythritol ester, and 89.34 parts polyalphaolefin.

[0092] The preparation method of the lubricating oil composition in this embodiment is the same as that in Example 6.

[0093] The lubricating oil compositions of Examples 6-10 and Comparative Examples 1-5 were subjected to performance tests, and the test results are shown in Table 1.

[0094] Table 1 Performance Tests of Lubricating Oil Compositions

[0095]

[0096]

[0097] Furthermore, the oxidation stability of the above-mentioned lubricating oil compositions was tested using SH / T 0565, and the oil film formation tendency of the lubricating oil compositions in Examples 6-10 and Comparative Examples 1-5 was tested using the DKA oxidation test method (170℃, 192h) and the dry TOST test, respectively. The test results are shown in Table 2.

[0098] Table 2 Results of Lubricating Oil Composition Coating Film Formation Tendency Test

[0099]

[0100] As shown in Table 2, compared to Comparative Examples 3-5 (without added phenolic ester antioxidants), the lubricating oil compositions in Examples 6-10 showed significantly reduced sludge formation in both the oxidation stability test and the dry TOS test, all below 30 mg. This indicates that the phenolic ester antioxidants in this application can enhance the antioxidant properties of the system. The formation of less varnish film on the inner wall of the glass tube after the DKA oxidation test indicates that the phenolic ester antioxidants in this application have a strong inhibitory effect on varnish film formation and exhibit excellent detergency and dispersibility.

[0101] In Comparative Example 1, where the amount of phenolic ester antioxidant added was less than 0.05 parts, the amount of sludge formed also reached more than 110 mg, and a varnish film was formed. This indicates that when the amount of phenolic ester antioxidant added is low, its effect on the tendency of oil to form a varnish film is not significant. In Comparative Example 2, where the amount of phenolic ester antioxidant added was greater than 0.3 parts, the amount of sludge formed also reached more than 80 mg, and a varnish film was formed. Moreover, the lubricating oil composition in Comparative Example 2 performed worse in the copper strip corrosion test and the liquid phase corrosion test, indicating that excessive addition of phenolic ester antioxidant will affect the anti-rust performance of the lubricating oil composition.

[0102] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," just as "comprising" is interpreted as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

Claims

1. A phenolic ester antioxidant, characterized in that, The structural formula of the phenolic ester antioxidant is shown in formula (I). Where x = 1 to 5, n = 12 to 20.

2. The phenolic ester antioxidant according to claim 1, characterized in that, In equation (I), x = 1 to 2, and n = 12 to 16.

3. A method for preparing the phenolic ester antioxidant according to claim 1 or 2, characterized in that, include: Alkylphenol and formaldehyde were mixed at 50–55°C under nitrogen protection to synthesize the first intermediate. The first intermediate and polyethylene polyamine were mixed at 50–55°C under nitrogen protection to synthesize the second intermediate. The third intermediate was synthesized by mixing alkylphenol and triethyl phosphite with anhydrous potassium carbonate as a catalyst. The second and third intermediates are mixed, and anhydrous potassium carbonate is used as a catalyst to synthesize phenolic ester antioxidants.

4. The method for preparing phenolic ester antioxidants according to claim 3, characterized in that, The mass ratio of the alkylphenol, formaldehyde, and polyethylene polyamine is 1:(2-2.5):(1-1.2); The mass ratio of the alkylphenol to the triethyl phosphite is 1:(1-1.1); The mass ratio of the second intermediate to the third intermediate is 1:(2 to 2.2).

5. The use of the phenolic ester antioxidant according to any one of claims 1 or 2 in a lubricating oil composition.

6. A lubricating oil composition, characterized in that, Includes the phenolic ester antioxidants as described in any one of claims 1 to 2.

7. The lubricating oil composition according to claim 6, characterized in that, The components include the following parts by mass: 0.05-0.3 parts of the phenolic ester antioxidant, 0.2-0.5 parts of the compound antioxidant, 0.03-0.05 parts of the metal passivator, 0.01-0.02 parts of the demulsifier, 0.01-0.02 parts of the antifoaming agent, 0.02-0.03 parts of the extreme pressure anti-wear agent, 0.03-0.05 parts of the rust inhibitor, and 99.2-99.4 parts of the base oil.

8. The lubricating oil composition according to claim 7, characterized in that, The compound antioxidants include phenolic antioxidants and / or amine antioxidants.

9. The lubricating oil composition according to claim 8, characterized in that, The phenolic antioxidants include 2,6-di-tert-butyl-p-cresol; The amine antioxidants include one or more of the following: octylphenyl-α-naphthylamine, dioctyl diphenylamine, dinonyl diphenylamine, octylbutyl diphenylamine, nonylbutyl diphenylamine, styryloctyl diphenylamine, and α-methylstyryl diphenylamine.

10. The lubricating oil composition according to claim 7, characterized in that, The metal passivating agent includes one or more of alkylthiadiazole, methylbenztriazole and N,N'-disaline diamine; The demulsifier includes oil-soluble polyether; The extreme pressure anti-wear agent includes one or more of di-n-butyl phosphite, triaryl phosphate, and trialkyl phosphate; The antifoaming agent includes one or more of polyacrylate, polymethyl methacrylate, No. 1 composite antifoaming agent and No. 2 composite antifoaming agent; The rust inhibitor includes succinic anhydride; The base oil comprises polyalphaolefins and pentaerythritol esters.

11. The use of the lubricating oil composition according to any one of claims 6 to 10 in a centrifugal compressor.

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