Preparation method of arylamine oligomerization coupling antioxidant and lubricating oil composition

Abstract

The invention provides a preparation method of an arylamine oligomerization coupling antioxidant and a lubricating oil composition containing the arylamine oligomerization coupling antioxidant. The preparation method of the arylamine oligomerization coupling antioxidant is shown in the specification. The arylamine oligomerization coupling antioxidant prepared by the method disclosed by the invention has excellent high-temperature oxidation resistance. The lubricating oil composition has excellent high-temperature oxidation resistance, corrosion resistance and sediment generation resistance, the performance of the lubricating oil composition is superior to that of a commercially available 5 mm < 2 > / s polyol ester base oil product, the use requirement of MIL-PRF-23699G aviation turbine engine lubricating oil can be met, and the high-temperature oxidation resistance and high-temperature lubricating performance of an aviation engine can be remarkably improved.

Description

Technical Field

[0001] The invention relates to an antioxidant, in particular to a preparation method of an aromatic amine oligomeric coupled antioxidant and a lubricating oil composition containing the antioxidant. Background Art

[0002] Aviation engine lubricating oil is an important material to ensure the normal operation of aviation engines and an important component of modern aviation fuel. The lubricating oil added to aviation turbine engines and transmission devices plays important roles such as lubrication, cooling, cleaning, sealing, rust prevention, and shock absorption.

[0003] In order to continuously improve the thrust of aircraft engines, the temperature before the aircraft engine turbine is getting higher and higher, so the working temperature of aviation lubricants is getting higher and higher. At present, the bearing temperature of turbofan engines has reached more than 260°C, and the main working temperature of its lubricant has risen to about 220°C. This requires the use of high-temperature stable engine lubricants to improve the high-temperature anti-oxidation, anti-sedimentation and anti-coking properties of the lubricant to meet the lubrication needs of bearings at high temperatures. The lubricant specifications for aviation turbine engines widely used in the world mainly include MIL-PRF-23699G "Performance Specifications for Synthetic Lubricants for Aviation Turbine Engines" (2014) and SAE AS 5780D "Specifications for Aviation Gas Turbine Engine Lubricants" (2018). Among them, HTS high thermal stability and HPC high-performance aircraft engine lubricants require lubricants to have excellent high temperature resistance and anti-oxidation properties, which can meet the long-term operating temperature of 220°C and reach the upper limit of high temperature use of 230°C. In the existing technology, high thermal stability polyol ester base oil and aromatic amine high temperature antioxidant are key materials for achieving high temperature lubrication performance of aircraft engine lubricants.

[0004] The polyol ester base oils currently available on the market or disclosed in the literature are mainly polyols and C 5～10 The product of esterification reaction of saturated monobasic fatty acid. The aromatic amine high temperature antioxidants available on the market or disclosed in the literature are mainly aromatic amine oligomeric coupled antioxidants. For example, CN114478282A discloses an ester base oil and aromatic amine oligomeric coupled antioxidant for aviation lubricating oil, wherein the ester base oil is a mixture of one or more of ethylene glycol, trimethylolpropane, monopentaerythritol, dipentaerythritol, tripentaerythritol and C 3～20 The product of esterification reaction of fatty acid; wherein the aromatic amine oligomeric coupled antioxidant is one or more of phenyl-α-naphthylamine, alkylated diphenylamine, alkylated phenyl-α-naphthylamine in C 3～20 The product generated by oligomerization coupling under the action of fatty acid ester base oil and organic peroxide.

[0005] Although the polyol ester base oil and aromatic amine high-temperature antioxidant in the existing technology have good high-temperature antioxidant properties, they are still insufficient in comprehensive performance such as high-temperature oxidation stability, corrosion resistance and resistance to deposit formation, and it is difficult to meet the performance requirements of high-performance aircraft engines. Therefore, further improvement is still needed. Summary of the invention

[0006] The invention provides a preparation method of an aromatic amine oligomeric coupled antioxidant and a lubricating oil composition.

[0007] The preparation method of the aromatic amine oligomeric coupled antioxidant of the present invention comprises the following steps:

[0008] (1) Excess monopentaerythritol and C 3～16 The dibasic fatty acid undergoes esterification reaction to obtain esterification product A1;

[0009] (2) the esterification product A1 described in step (1) is reacted with excess C 4～10 The monobasic fatty acid undergoes esterification reaction to obtain crude esterification product B1, which is purified to obtain pentaerythritol ester;

[0010] (3) The pentaerythritol ester prepared in step (2) is mixed with one or more of alkylated diphenylamine, phenyl-α-naphthylamine and alkylated phenyl-α-naphthylamine, and an organic peroxide is added under a nitrogen atmosphere to carry out an oligomeric coupling reaction, and the product is collected to obtain the aromatic amine oligomeric coupled antioxidant of the present invention.

[0011] According to the present invention, in step (1), the monopentaerythritol and C 3～16 The molar ratio of the dibasic fatty acid can be (2.05-100):1, preferably (3-60):1, and more preferably (3-30):1; in step (2), the hydroxyl group and C in the esterification product A1 4～10 The molar ratio of the carboxyl groups in the monobasic fatty acid may be 1:(1.05-1.30), preferably 1:(1.10-1.20).

[0012] According to the present invention, the reaction temperature of step (1) is 50-180°C, preferably 80-150°C, and the reaction time is 1-20h, preferably 2-10h; the reaction temperature of step (2) is 50-250°C, preferably 100-220°C, and the reaction time is until no more water is produced, which can generally be 1-20h, or 5-10h.

[0013] According to the present invention, the dibasic fatty acid can be one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, and hexadecanedioic acid. Further preferably, the dibasic fatty acid can be one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid.

[0014] According to the present invention, the monobasic fatty acid is preferably selected from two or more (for example, three, four, five, six or seven) of n-butyric acid, isobutyric acid, n-pentanoic acid, isovaleric acid, n-hexanoic acid, isohexanoic acid, n-heptanoic acid, isoheptanoic acid, n-octanoic acid, isooctanoic acid, n-nonanoic acid, isononanoic acid, n-decanoic acid and isodecanoic acid, more preferably selected from two or more (for example, three, four, five, six or seven) of n-butyric acid, n-pentanoic acid, n-hexanoic acid, n-heptanoic acid, n-octanoic acid, n-nonanoic acid and n-decanoic acid, further preferably, the monobasic fatty acid may include 0-10 mol% of n-butyric acid, 5 mol%-80 mol% of n-pentanoic acid, 5 mol%-35 mol% of n-hexanoic acid, 5 mol%-25 mol% of n-heptanoic acid, 0-20 mol% of n-octanoic acid, 0-15 mol% of n-nonanoic acid and 0-10 mol% of n-decanoic acid.

[0015] According to the present invention, a catalyst may be added to the esterification reaction of step (1) and / or step (2), and the catalyst includes one or more of concentrated sulfuric acid, sodium bisulfate, p-toluenesulfonic acid, zinc oxide, cation exchange resin, ionic liquid, stannous oxide, titanate and activated carbon. The amount of the catalyst added may comply with the amount used in the esterification reaction in the prior art and is not particularly limited. The catalyst may be removed by methods known in the art such as alkali washing, water washing and filtering after the esterification reaction is completed and is not particularly limited.

[0016] According to the present invention, a solvent may be added to the esterification reaction of step (1) and / or step (2), and the solvent may be one or more of xylene, toluene, and cyclohexane. The amount of the solvent added may comply with the amount used in the esterification reaction in the prior art, and is not particularly limited. The solvent may be removed by a method known in the art such as distillation after the esterification reaction is completed, and is not particularly limited.

[0017] According to the present invention, the esterification reaction in step (1) and / or step (2) can be carried out under nitrogen protection.

[0018] According to the present invention, in step (2), the method for purifying the crude esterification product B1 includes one or more of reduced pressure distillation, alkali washing, water washing, dehydration, decolorization, and filtering. After the purification treatment, pentaerythritol ester with higher purity can be obtained.

[0019] According to the present invention, in step (3), the mass ratio between the pentaerythritol ester prepared in step (2) and one or more of alkylated diphenylamine, phenyl-α-naphthylamine and alkylated phenyl-α-naphthylamine can be 1:0.1-5, preferably 1:0.2-2.

[0020] According to the present invention, in step (3), the molar ratio between one or more of the alkylated diphenylamine, phenyl-α-naphthylamine and alkylated phenyl-α-naphthylamine and the organic peroxide can be 1:0.5-10, preferably 1:1-5.

[0021] According to the present invention, the reaction temperature of step (3) is 50 to 150° C., preferably 70 to 140° C., and the reaction time is 1 to 20 hours, preferably 2 to 10 hours.

[0022] According to the present invention, in step (3), the alkylated diphenylamine can be selected from C4-C8 alkylated diphenylamines, such as 4,4'-diisooctyl-diphenylamine, 4,4'-dibutyl-diphenylamine, 4-isooctyl-4'-butyl-diphenylamine, 4-butyl-diphenylamine, 4-isooctyl-diphenylamine. The alkylated diphenylamine can be selected from existing commercial products, such as Vanderbilt V81, T534, etc.

[0023] According to the present invention, in step (3), the alkylated phenyl-α-naphthylamine can be selected from one or more of N-isooctylphenyl-α-naphthylamine, hexylphenyl-α-naphthylamine, and butylphenyl-α-naphthylamine. The alkylated phenyl-α-naphthylamine can be selected from existing commercial products, such as T531, BASF L06, etc.

[0024] According to the present invention, in step (3), the organic peroxide may be selected from one or more of di-tert-butyl peroxide, dihexyl peroxide and diphenyl peroxide.

[0025] According to the present invention, in step (3), the product can be purified, and the purification method includes one or more of reduced pressure distillation, alkali washing, water washing, dehydration, decolorization, and filtering. After the purification treatment, a higher purity aromatic amine oligomeric coupled antioxidant can be obtained.

[0026] The aromatic amine oligomeric coupled antioxidant prepared according to the method of the invention has excellent high-temperature antioxidant performance.

[0027] The invention also provides a lubricating oil composition.

[0028] The lubricating oil composition of the present invention comprises the aforementioned aromatic amine oligomeric coupled antioxidant, extreme pressure anti-wear agent, rust inhibitor and pentaerythritol ester, wherein the aromatic amine oligomeric coupled antioxidant accounts for 0.5% to 10% of the total mass of the lubricating oil composition, the extreme pressure anti-wear agent accounts for 0.1% to 5% of the total mass of the lubricating oil composition, the rust inhibitor accounts for 0.01% to 1% of the total mass of the lubricating oil composition, and the pentaerythritol ester accounts for 85% to 98% of the total mass of the lubricating oil composition;

[0029] The preparation method of the pentaerythritol ester is as follows:

[0030] (1) Excess monopentaerythritol and C 3～16 The dibasic fatty acid undergoes esterification reaction to obtain esterification product A1;

[0031] (2) the esterification product A1 described in step (1) is reacted with excess C 4～10 The monobasic fatty acid undergoes esterification reaction to obtain crude esterification product B1, which is purified to obtain pentaerythritol ester.

[0032] According to the present invention, the pentaerythritol ester in the lubricating oil composition is the pentaerythritol ester prepared in step (2) in the preparation of the aforementioned aromatic amine oligomeric coupled antioxidant. Therefore, the reaction raw materials and reaction conditions in steps (1) and (2) of preparing the pentaerythritol ester are the same as the reaction raw materials and reaction conditions in steps (1) and (2) of preparing the aforementioned aromatic amine oligomeric coupled antioxidant, and are not described in detail herein.

[0033] According to the present invention, in the lubricating oil composition, the pentaerythritol ester is used as a lubricating base oil.

[0034] According to the present invention, the pentaerythritol ester has a high viscosity index (>130), a low pour point (<-60°C), a relatively low kinematic viscosity at -40°C (<10000mm 2 / s) and good high temperature oxidation stability, which can meet the use requirements of MIL-PRF-23699G aviation turbine engine lubricating oil.

[0035] According to the present invention, in the lubricating oil composition, the extreme pressure anti-wear agent can be selected from phosphate esters and / or phosphate amine salts, and common trade names include TCP, BASF 349, AW6110, etc.; the rust inhibitor can be selected from benzotriazole derivatives, such as 5-methylbenzotriazole, T551, etc.

[0036] The lubricating oil composition of the present invention has excellent high temperature oxidation resistance, corrosion resistance and anti-deposit formation ability, and its performance is better than that of commercially available 5mm 2 / s polyol ester base oil products can meet the use requirements of MIL-PRF-23699G aviation turbine engine lubricants and can significantly improve the high-temperature oxidation resistance and high-temperature lubrication performance of aviation engines. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below by examples, but the present invention is not limited thereto.

[0038] The main sources of raw materials used are as follows:

[0039] The present invention is to monopentaerythritol PE, C 4～10 Monobasic fatty acids, C 3～16 The source of the dibasic fatty acid is not particularly limited, and any commercially available product or homemade product of the above raw materials known to those skilled in the art may be used.

[0040] Mixed pentaerythritol ester MIXPE1, commercially available, Zhejiang Quzhou Chemical Co., Ltd., kinematic viscosity at 100℃ 5.02mm 2 / s

[0041] Antioxidant: Vanderbilt V81, 4,4'-diisooctyl-diphenylamine, Vanderbilt Corporation, USA Antioxidant: BASF L06, N-isooctylphenyl-α-naphthylamine, BASF Chemical Co., Ltd.

[0042] Aromatic amine oligomeric coupled antioxidant: V9317, Vanderbilt Corporation, USA

[0043] Rust inhibitor: 5-methylbenzotriazole, Shanghai Chemical Plant, chemically pure

[0044] Extreme pressure anti-wear agent: Tricresyl phosphate, TCP, Zibo Huihua Chemical Co., Ltd.

[0045] Di-tert-butyl peroxide, 97%, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0046] Example 1

[0047] In a 1L four-necked flask equipped with a stirring rod, a thermometer, a condenser, and a water separator, 100.0g of monopentaerythritol (0.734mol), 12.0g of adipic acid (0.082mol), 150ml of xylene, and 3.0g of tetrabutyl titanate catalyst were added, and the mixture was reacted at 150°C for 5h under nitrogen protection to obtain an esterification product A1, and then cooled to room temperature; then 145.0g of n-pentanoic acid, 150.0g of n-hexanoic acid, 90.0g of n-heptanoic acid, 15.0g of n-octanoic acid, and 4.0g of tetrabutyl titanate catalyst were added, and the reaction temperature was heated to 150°C under nitrogen protection, and then the temperature was raised to 220°C at a rate of 10°C / h, and the reaction was continued until no water was produced to obtain an esterification crude product B1, which was cooled to room temperature, and then treated with reduced pressure distillation, alkali washing, water washing, dehydration, decolorization, and filtration to obtain pentaerythritol ester, which was numbered as HPCE2A;

[0048] In a 500mL three-necked flask equipped with a thermometer, an addition funnel and a reflux condenser, 39.2g of diisooctyldiphenylamine V81 (0.10mol), 16.5g of N-(p-isooctylphenyl)-α-naphthylamine L06 (0.050mol) and 60.0g of pentaerythritol ester HPCE2 were added, and the mixture was stirred. The temperature was raised to 130°C under a nitrogen atmosphere, and 44.0g (0.30mol) of di-tert-butyl peroxide was slowly added. The oligomerization coupling reaction was carried out at 130°C for 8h. After the reaction was completed, the impurity products were removed by distillation under reduced pressure, and a dark brown viscous liquid was obtained after filtration, which was the aromatic amine oligomer coupling antioxidant of the present invention, numbered SynAOM1.

[0049] Example 2

[0050] In a 1L four-necked flask equipped with a stirring rod, a thermometer, a condenser, and a water separator, 100.0g of monopentaerythritol (0.734mol), 7.40g of malonic acid (0.0705mol), 10.7g of adipic acid (0.0734mol), 150ml of xylene, and 3.0g of tetrabutyl titanate catalyst were added, and the mixture was reacted at 150°C for 5h under nitrogen protection to obtain an esterification product A1, and then cooled to room temperature; then 270.0g of n-pentanoic acid, 85.0g of n-hexanoic acid, 58.0g of n-heptanoic acid, and 3.0g of tetrabutyl titanate catalyst were added, and the reaction temperature was heated to 150°C under nitrogen protection, and then the temperature was raised to 220°C at a rate of 10°C / h, and the reaction was continued until no water was produced to obtain an esterification crude product B1, which was cooled to room temperature, and then treated with reduced pressure distillation, alkali washing, water washing, dehydration, decolorization, and filtration to obtain pentaerythritol ester, which was numbered HPCE2B;

[0051] In a 500mL three-necked flask equipped with a thermometer, an addition funnel and a reflux condenser, 78.4g of diisooctyldiphenylamine V81 (0.2mol) and 100.0g of pentaerythritol ester HPCE2B were added, and the mixture was stirred. The temperature was raised to 130°C under a nitrogen atmosphere, and 58.0g (0.40mol) of di-tert-butyl peroxide was slowly added. The oligomerization coupling reaction was carried out at 130°C for 8h. After the reaction was completed, the impurity products were removed by distillation under reduced pressure, and a dark brown viscous liquid was obtained after filtration, which was the aromatic amine oligomer coupling antioxidant of the present invention, numbered SynAOM2.

[0052] The lubricating oil composition 1 of the present invention and comparative lubricating oil compositions 1 and 2 were prepared according to the formulations shown in Table 1, and the anti-oxidation performance and anti-corrosion performance of these lubricating oil compositions were evaluated.

[0053] Table 1 Lubricating oil composition formula

[0054]

[0055] The lubricating oil compositions were subjected to oxidation induction period determination, 218°C corrosion and oxidation stability assessment tests, and the test results are shown in Table 2. The oxidation induction period was determined by Pressure Differential Scanning Calorimetry (PDSC), and the test method standard is SH / T0719-2002 Lubricating Oil Oxidation Induction Period Determination Method (Pressure Differential Scanning Calorimetry). The corrosion and oxidation stability assessment test method is the method FED STD-791-5308 specified by MIL-PRF-23699G, and the experimental conditions are: dry air is passed through at a constant temperature of 218°C for oxidation for 72 hours, the oxygen flow rate is 50-83mL / min, and the metal test pieces are steel, silver, titanium, aluminum, and titanium of specific specifications. The evaluation index is the change in the total acid value of the lubricating oil before and after oxidation (△TAN / mgKOH·g -1 )、40℃ kinematic viscosity change rate (△Viscosity%)、100mL oil deposit formation amount (Deposit / mg·(100mL) -1 ) and the mass change per unit area of ​​metal test pieces such as metal steel, silver, aluminum, titanium, etc. The present invention uses the mass change data of the steel sheet to evaluate the experimental results.

[0056] It can be seen from the data in Table 2 that the lubricating oil composition of the present invention has better high temperature oxidation stability, corrosion resistance and deposit resistance, and is superior to the combination of conventional polyol ester base oil and commercially available aromatic amine oligomeric antioxidant.

[0057] Table 2 Oxidation induction period OIT and 218℃ corrosion and oxidation stability test results

[0058]

Claims

1. A method for preparing an aromatic amine oligomeric coupled antioxidant, comprising the following steps: (1) Excess monopentaerythritol and C 3～16 The dibasic fatty acid undergoes esterification reaction to obtain esterification product A1; (2) the esterification product A1 described in step (1) is reacted with excess C 4～10 The monobasic fatty acid undergoes esterification reaction to obtain crude esterification product B1, which is purified to obtain pentaerythritol ester; (3) The pentaerythritol ester prepared in step (2) is mixed with one or more of alkylated diphenylamine, phenyl-α-naphthylamine and alkylated phenyl-α-naphthylamine, and an organic peroxide is added under a nitrogen atmosphere to carry out an oligomerization coupling reaction, and the product is collected.

2. The preparation method according to claim 1, characterized in that: In step (1), the monopentaerythritol and C 3～16 The molar ratio of the dibasic fatty acid is (2.05-100):1; in step (2), the hydroxyl group and C in the esterification product A1 4～10 The molar ratio of the carboxyl group in the monobasic fatty acid is 1: (1.05～1.30)。 3. The preparation method according to claim 1, characterized in that: The reaction temperature of step (1) is 50-180° C., and the reaction time is 1-20 hours; the reaction temperature of step (2) is 50-250° C., and the reaction time is until no more water is produced.

4. The preparation method according to claim 1, characterized in that: The dibasic fatty acid is one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, and hexadecanedioic acid; the monobasic fatty acid is selected from two or more of n-butyric acid, isobutyric acid, n-valeric acid, isovaleric acid, n-hexanoic acid, isohexanoic acid, n-heptanoic acid, isoheptanoic acid, n-octanoic acid, isooctanoic acid, n-nonanoic acid, isononanoic acid, n-decanoic acid, and isodecanoic acid.

5. The preparation method according to claim 1, characterized in that: Adding a catalyst to the esterification reaction of step (1) and / or step (2), wherein the catalyst is selected from one or more of concentrated sulfuric acid, sodium bisulfate, p-toluenesulfonic acid, zinc oxide, cation exchange resin, ionic liquid, stannous oxide, titanate and activated carbon; and / or, The esterification reaction in step (1) and / or step (2) is carried out under nitrogen protection.

6. The preparation method according to claim 1, characterized in that: In step (3), the mass ratio of the pentaerythritol ester prepared in step (2) to one or more of alkylated diphenylamine, phenyl-α-naphthylamine and alkylated phenyl-α-naphthylamine is 1:0.1-5; the molar ratio of one or more of alkylated diphenylamine, phenyl-α-naphthylamine and alkylated phenyl-α-naphthylamine to the organic peroxide is 1:0.5-10.

7. The preparation method according to claim 1, characterized in that: The reaction temperature of step (3) is 50-150° C., and the reaction time is 1-20 hours.

8. The preparation method according to claim 1, characterized in that: In step (3), the alkylated diphenylamine is a C4-C8 alkylated diphenylamine; the alkylated phenyl-α-naphthylamine is one or more of N-isooctylphenyl-α-naphthylamine, hexylphenyl-α-naphthylamine, and butylphenyl-α-naphthylamine; and the organic peroxide is one or more of di-tert-butyl peroxide, dihexyl peroxide, and diphenyl peroxide.

9. A lubricating oil composition comprising an aromatic amine oligomeric coupled antioxidant, an extreme pressure antiwear agent, a rust inhibitor and a pentaerythritol ester prepared according to the method of any one of claims 1 to 8, wherein the aromatic amine oligomeric coupled antioxidant accounts for 0.5% to 10% of the total mass of the lubricating oil composition, the extreme pressure antiwear agent accounts for 0.1% to 5% of the total mass of the lubricating oil composition, the rust inhibitor accounts for 0.01% to 1% of the total mass of the lubricating oil composition, and the pentaerythritol ester accounts for 85% to 98% of the total mass of the lubricating oil composition.

10. The lubricating oil composition according to claim 9, characterized in that The preparation method of the pentaerythritol ester is: (1) Excess monopentaerythritol and C 3～16 The dibasic fatty acid undergoes esterification reaction to obtain esterification product A1; (2) the esterification product A1 described in step (1) is reacted with excess C 4～10 The monobasic fatty acid undergoes esterification reaction to obtain crude esterification product B1, which is purified to obtain pentaerythritol ester.

11. The lubricating oil composition according to claim 9, characterized in that The extreme pressure anti-wear agent is selected from phosphate esters and / or phosphate amine salts; the rust inhibitor is selected from benzotriazole derivatives.

Images