CN115992028B - Antioxidant composition and preparation method thereof - Google Patents

Abstract

The present invention provides an antioxidant composition and a preparation method thereof. The antioxidant composition of the present invention comprises an ester compound and a multifunctional oiliness agent, wherein the structure of the ester compound is shown in formula (I): In formula (I), there is at least one A group selected from the monovalent group represented by formula (II); The definitions of the groups are as described in the specification; the multifunctional oiliness agent is the reaction product of alkyl benzotriazole and/or benzotriazole and mixed alkyl primary amine under the action of an acid catalyst. The antioxidant composition of the present invention can significantly improve the oxidation stability and high temperature corrosion resistance of lubricating oil, especially synthetic lubricating oil, and is particularly suitable for aviation synthetic ester lubricating oil.

Description

Antioxidant composition and preparation method thereof

Technical Field

The invention relates to an antioxidant composition, in particular to an antioxidant composition which can be used in aviation synthetic ester lubricating oil and has high-temperature antioxidant and anti-corrosion properties.

Background Art

The high-temperature corrosion and oxidation stability of aircraft engine lubricating oil refers to the ability of lubricating oil to resist high-temperature oxidation and alleviate high-temperature deposition during use, which is an important manifestation of the high-temperature oxidation resistance of aircraft engine oil. Under the induction of high-temperature oxygen and the catalytic action of metals, lubricating oil undergoes a series of chemical changes such as oxidation, polymerization, alkylation, and decomposition in a short period of time, causing the engine oil to produce a large amount of sediment such as sludge, which adheres to metal accessories, pistons and rings, and severely corrodes equipment, shortening the service life of equipment and seriously affecting the normal operation of aircraft engines. Improving the high-temperature corrosion and oxidation stability of aircraft engine oil is of great significance to improving the working efficiency and service life of lubrication system equipment.

With the development of the aviation industry and the increase in aircraft flight speed, the main operating temperature of turbojet engine lubricants has increased from the early 80°C to the current 220°C. It is expected that the main temperature of the next generation of aircraft engine lubricants will exceed 350°C. The high temperature, high speed and high load environmental characteristics of aircraft engines have put forward higher and higher requirements on the performance of aircraft engine lubricants. When the outlet temperature of the aircraft engine is above 200°C, the oxidation rate of ordinary engine lubricants will increase exponentially, resulting in increased viscosity of the lubricant, increased total acid value, strong corrosiveness, and the generation of a large amount of sediment. In order to effectively alleviate these problems, it is necessary to improve the high temperature corrosion and oxidation stability of aircraft engine lubricants. These properties are directly related to the service life of aircraft engine lubricants and the working efficiency of engine lubrication system components.

The high temperature corrosion and oxidation stability of aviation engine oil are closely related to the structure and high temperature performance of base oil and antioxidant. Therefore, to effectively improve the high temperature corrosion and oxidation stability of aviation engine oil, it is necessary to synthesize high temperature antioxidants with excellent chemical structure and high temperature oxidation resistance, so as to effectively protect the base oil, reduce the generation of oxidation products, improve the oil solubility of oxidation products, reduce sediments, and effectively alleviate the deterioration and deposition of aviation engine lubricants under high temperature conditions.

The internationally renowned aviation lubricant specification MIL-PRF-7808L specification has a 100°C kinematic viscosity grade of four centistokes (4mm ² /s) for aircraft engine lubricants. This requires both good high-temperature oxidation resistance and low-temperature fluidity, thereby ensuring the rapid flight of aircraft at high temperatures, high speeds, and high loads, and ensuring the rapid takeoff, maneuverability, high-speed cruising, and safe landing of aircraft in high-cold areas. It is necessary to synthesize a high-temperature antioxidant with excellent chemical structure and high-temperature oxidation resistance, so as to effectively protect the base oil, reduce the generation of oxidation products, reduce sediments, and effectively alleviate the high-temperature oil deterioration and deposition problems of aviation engine oil, thereby ensuring the high-temperature safe and stable operation of aircraft engines. At the same time, the lubricant composition is maintained to have a lower kinematic viscosity at low temperatures and better low-temperature fluidity, meeting the MIL-PRF-7808L specification of kinematic viscosity ≤20000 (mm ² /s) at -51°C, which is more conducive to the low-temperature lubrication service of lubricants and the safe and rapid start-up flight of aircraft in low-temperature environments.

The purpose of the application of oiliness agent is to reduce friction. It dissolves in lubricating oil and forms a strong directional adsorption film on the friction surface, which reduces the friction and wear between moving parts and improves the friction performance of lubricating oil. There are many types of oiliness agents, mainly animal and vegetable oils, higher fatty acids, higher fatty alcohols, amines, amides, esters, sulfurized oils, etc. At present, the commonly used oiliness agents in China are sulfurized cottonseed oil, fatty acid esters, benzotriazole fatty acid amine salts, etc. Benzotriazole fatty acid amine salts have oil solubility, anti-wear, anti-oxidation, anti-corrosion, and anti-rust properties. It is added to natural mineral oils and lubricating oils as a rust inhibitor, antioxidant, metal passivator, anti-wear agent, preservative, etc., and has achieved good results. It can be used in gear oil, hyperbolic gear oil, anti-wear hydraulic oil, oil film bearing oil, grease, and can also be used as a rust inhibitor and vapor phase corrosion inhibitor in rust-proof grease.

Patents and literature have introduced methods for preparing benzotriazole derivatives, but the methods either have strict reaction conditions or are difficult to separate and purify, resulting in low product yields.

The product obtained by the original process is a light yellow flocculent solid. The product has certain oil solubility, anti-wear, anti-oxidation, anti-corrosion, and anti-rust properties. However, the disadvantage is that it has poor oil solubility under low temperature conditions and is easy to precipitate, making the lubricating oil turbid. It will settle after long-term storage, which is not conducive to the performance of the oil under low temperature conditions. In addition, the flocculent solid benzotriazole fatty acid ammonium salt is not convenient for blending oil products during the actual production process of lubricating oil, while the liquid benzotriazole fatty acid ammonium salt has obvious advantages in this regard.

US 3,697,427 discloses the use of benzotriazole or certain alkylbenzotriazole as metal deactivators in synthetic lubricating oil components. US 3,790,481 discloses the use of methylbisbenzotriazole, benzotriazole, alkylbenzotriazole, and naphthazole as copper deactivators in polyol ester lubricating oil components.

US 5,076,946 discloses the use of a methyl dialkylbenzotriazole dimer derivative as a metal deactivator in lubricating oil to improve the oxidation stability of the lubricating oil. US 6,743,759B2 discloses the compounding of methylene bis-di-tert-butyl-dithiocarbamate with derivatives of alkylbenzotriazole and diphenylamine in a certain proportion to form a lubricating oil antioxidant extreme pressure antiwear agent with good performance.

Summary of the invention

The present invention provides an antioxidant composition and a preparation method thereof and a lubricating oil composition containing the antioxidant composition, including the following aspects.

In a first aspect, the present invention provides an antioxidant composition.

The antioxidant composition of the present invention comprises an ester compound and a multifunctional oiliness agent, wherein the structure of the ester compound is shown in formula (I):

In formula (I), n is an integer between 1 and 10, preferably an integer between 1 and 5, and more preferably an integer between 1 and 3; _R0 is selected from n-valent _C1-30 straight or branched alkyl, _C2-30 straight or branched heteroalkyl, preferably selected from n-valent _C1-20 straight or branched alkyl, _C2-20 straight or branched heteroalkyl, more preferably selected from n-valent _C1-10 straight or branched alkyl, _C2-10 straight or branched heteroalkyl; each R' group is independently selected from _C1-10 straight or branched alkylene, preferably selected from _C1-5 straight or branched alkylene, more preferably selected from _C1-3 straight or branched alkylene; each R" group is independently selected from _C1-30 straight or branched alkyl, preferably selected from _C1-20 straight or branched alkyl, more preferably selected from _C1-10 straight or branched alkyl; each R"' group is independently selected from C _1-30 straight or branched chain alkyl, preferably selected from C _1-20 straight or branched chain alkyl, more preferably selected from C _1-10 straight or branched chain alkyl; each A group is selected from the monovalent group represented by formula (II), H, C _1-20 straight or branched chain alkyl, preferably selected from the group represented by formula (II), H, C _1-10 straight or branched chain alkyl, more preferably selected from the group represented by formula (II), H, C _1-5 straight or branched chain alkyl, and at least one A group in formula (I) is selected from the monovalent group represented by formula (II);

Formula (II) is a monovalent group formed by m structural units represented by formula (III) bonded to each other,

In formula (II), m is an integer between 1 and 10, preferably an integer between 1 and 5, and more preferably an integer between 1 and 3; each R _I group is independently selected from H, C _1-10 straight chain or branched alkyl, preferably selected from H, C _1-5 straight chain or branched alkyl, more preferably selected from H, C _1-3 straight chain or branched alkyl; each x is independently selected from an integer between 0 and 4, preferably an integer between 0 and 2, and more preferably 0 or 1; each R _II group is independently selected from H, C _1-10 straight chain or branched alkyl, preferably selected from H, C _1-5 straight chain or branched alkyl, more preferably selected from H, C _1-3 straight chain or branched alkyl; each y is independently selected from an integer between 0 and 2, preferably 0 or 1; each R _III group is independently selected from H, C _1-10 straight chain or branched alkyl, preferably selected from H, C _1-5 straight chain or branched alkyl, more preferably selected from H, C _{1 to 3} straight or branched alkyl groups; each z is independently selected from an integer between 0 and 3, preferably an integer between 0 and 2, more preferably 0 or 1;

Each L _I , L _II , and L _III in formula (II) is independently H, a C _1-4 alkyl group, a binding end bonded to L _I , L _II , and L _III in different structural units, a binding end bonded to formula (I), or a monovalent group represented by formula (IV); in formula (II), only one L _I , L _II , or L _III is a binding end bonded to formula (I);

The △ in the monovalent group represented by formula (IV) represents a bonding end bonded to L _I , L _II or L _III ;

In formula (IV), n' is an integer between 1 and 10, preferably an integer between 1 and 5, and more preferably an integer between 1 and 3; _R0 is selected from n-valent _C1-30 straight or branched alkyl, _C2-30 straight or branched heteroalkyl, preferably selected from n-valent _C1-20 straight or branched alkyl, _C2-20 straight or branched heteroalkyl, more preferably selected from n-valent _C1-10 straight or branched alkyl, _C2-10 straight or branched heteroalkyl; each R' group is independently selected from _C1-10 straight or branched alkylene, preferably selected from _C1-5 straight or branched alkylene, more preferably selected from _C1-3 straight or branched alkylene; each R" group is independently selected from _C1-30 straight or branched alkyl, preferably selected from _C1-20 straight or branched alkyl, more preferably selected from _C1-10 straight or branched alkyl; each R"' group is independently selected from C _{The 1-30} straight chain or branched chain alkyl group is preferably selected from C _1-20 straight chain or branched chain alkyl groups, and more preferably selected from C _1-10 straight chain or branched chain alkyl groups.

According to the present invention, preferably, in formula (II), L _I , L _II , and L _III in the same structural unit are not bonded to each other.

According to the present invention, in formula (II), when m=1, one of L _I , L _II , and L _III is the binding end bonded to formula (I), and the other two are each independently H, C _1-4 alkyl, or a monovalent group represented by formula (IV).

According to the present invention, in formula (II), when m=2, there are two structural units as shown in formula (III), and L _I , L _II , and L _III (when they are all bonded binding ends) in the two structural units can be bonded to each other. Optionally, only one L _I , L _II or L _III exists between the two structural units to bond to each other, that is, only one covalent bond is formed between the two different structural units.

According to the present invention, in formula (II), when m is greater than 2, there are m structural units as shown in formula (III), and L _I , L _II , and L _III in the m structural units (when they are all bonded binding ends) can be bonded to each other. Further optionally, the m structural units are a structural unit at one end, (m-2) middle structural units and a structural unit at another end that are bonded in sequence, and there is only one L _I , L _II or L _III in each structural unit at the end that is bonded to L _I , L _II or L _III in the middle structural unit adjacent to it, and there are two L _I , L _II or L _III in each middle structural unit that are respectively bonded to L _I , L _II or L _III in the structural unit adjacent to it, that is, only one covalent bond is formed between every two connected different structural units.

According to the present invention, examples of the group represented by formula (II) include:

The * represents the terminal bonded to the formula (I).

According to the present invention, examples of the ester compounds include:

In the molecular structures of ester compounds P-1, P-2, and P-3, the group PAN represents the group (II), and the specific molecular structure of the group (II) is shown above. Taking (II-1) as an example, the molecular structure of the ester compound formed is as follows:

According to the present invention, the multifunctional oiliness agent is a reaction product of alkyl benzotriazole and/or benzotriazole and mixed alkyl primary amine under the action of an acidic catalyst.

According to the present invention, the preparation method of the multifunctional oiliness agent is: in the presence of an inert gas, alkyl benzotriazole and/or benzotriazole and alkyl primary amine are reacted under the action of an acidic catalyst, and the product is collected.

According to the present invention, the structure of the alkylbenzotriazole and/or benzotriazole is:

In the formula, R ₁ ' is selected from H, C ₁ ～C ₁₂ straight chain or branched chain alkyl, preferably C ₁ ～C ₈ straight chain or branched chain alkyl, and most preferably methyl.

According to the present invention, the alkyl primary amine is a C ₁₆ -C ₂₂ alkyl primary amine, and its structural formula is R ₂ 'CH ₂ NH ₂ , wherein R ₂ ' is a C ₁₅ -C ₂₁ straight chain or branched chain alkyl group.

According to the present invention, the alkyl primary amine is preferably a C ₁₆ -C ₂₂ mixed alkyl primary amine, and the mixed alkyl primary amine is a mixture of a linear primary amine and a branched primary amine.

According to the present invention, based on the total molar number of the mixed alkyl primary amines, in molar percentage, according to the alkyl type: the _C16 - _C22 mixed alkyl primary amines contain 55%-90% of _C16 - _C22 straight-chain alkyl primary amines and 10%-45% of _C16 - _C22 branched-chain alkyl primary amines, preferably contain 55%-80% of _C16 - _C22 straight-chain alkyl primary amines and 20%-45% of _C16 - _C22 branched-chain alkyl primary amines.

According to the present invention, based on the total molar number of the mixed alkyl primary amines, in terms of molar percentage, according to the carbon content: the content of _C16 - _C18 alkyl primary amines in the _C16 - _C22 mixed alkyl primary amines is 45%-85%, and the content of _C19 - _C22 alkyl primary amines is 15%-55%, preferably the content of _C16 - _C18 alkyl primary amines is 55%-75%, and the content of _C19 - _C22 alkyl primary amines is 25%-45%.

According to the present invention, based on the total molar number of the mixed alkyl primary amines, in terms of molar percentage, according to the carbon number and the alkyl type: in the _C16 - _C22 mixed alkyl primary amines, the content of _C16 - _C18 straight-chain primary amines is 40%-70%, the content of _C19 - _C22 straight-chain primary amines is 15-40%, the content of _C16 - _C18 branched-chain primary amines is 5%-35%, and the content of _C19 - _C22 branched-chain primary amines is 5%-30%; preferably, the content of _C16 - _C18 straight-chain primary amines is 45%-60%, the content of _C19 - _C22 straight-chain primary amines is 20%-35%, the content of _C16 - _C18 branched-chain primary amines is 5%-25%, and the content of _C19 -C22 branched-chain primary amines is 5%. The content of branched primary amine in ₂₂ is 5% to 30%.

According to the present invention, the acidic catalyst is preferably one or more of glacial acetic acid, acetic acid, sulfuric acid, hydrochloric acid, phosphoric acid, SO ₃ and P ₂ O ₅ or aqueous solutions of these substances and mixtures thereof, preferably sulfuric acid and/or glacial acetic acid or aqueous solutions thereof, most preferably glacial acetic acid or acetic acid with a mass percentage of 60% to 100%.

According to the present invention, the molar ratio between the alkyl benzotriazole and/or benzotriazole and the alkyl primary amine is 1:0.5-1, preferably 1:0.8-1.

According to the present invention, the mass ratio between the acid catalyst and the alkylbenzotriazole and/or benzotriazole is 1:0.5-5, preferably 1:0.8-4.

According to the present invention, the reaction temperature of alkylbenzotriazole and/or benzotriazole and alkyl primary amine under the action of acidic catalyst is 60°C to 100°C, preferably 80°C to 100°C, and the reaction time is usually as long as possible, generally 2h to 8h, preferably 3h to 6h.

According to the present invention, in the antioxidant composition, the mass ratio between the ester compound and the multifunctional oiliness agent is 10 to 60:1, preferably 15 to 50:1.

According to the present invention, the antioxidant composition optionally includes an amine compound, and the amine compound is selected from the compound represented by formula (II');

Formula (II') is a compound formed by m' structural units shown in formula (III') bonded to each other,

In formula (II'), m' is an integer between 1 and 10, preferably an integer between 1 and 5, and more preferably an integer between 1 and 3; each R _I group is independently selected from H, C _1-10 straight chain or branched alkyl, preferably selected from H, C _1-5 straight chain or branched alkyl, and more preferably selected from H, C _1-3 straight chain or branched alkyl; each x is independently selected from an integer between 0 and 4, preferably an integer between 0 and 2, and more preferably 0 or 1; each R _II group is independently selected from H, C _1-10 straight chain or branched alkyl, preferably selected from H, C _1-5 straight chain or branched alkyl, and more preferably selected from H, C _1-3 straight chain or branched alkyl; each y is independently selected from an integer between 0 and 2, and preferably 0 or 1; each R _III group is independently selected from H, C _1-10 straight chain or branched alkyl, preferably selected from H, C _1-5 straight chain or branched alkyl, and more preferably selected from H, C _{1 to 3} straight or branched alkyl groups; each z is independently selected from an integer between 0 and 3, preferably an integer between 0 and 2, more preferably 0 or 1;

In formula (II'), each of L _I ″, L _II ″, and L _III ″ is independently H, a C _1-4 alkyl group, or a terminal bonded to L _I ″, L _II ″, and L _III ″ in different structural units.

According to the present invention, preferably, in formula (II'), L _I ″, L _II ″, and L _III ″ in the same structural unit are not bonded to each other.

According to the present invention, in formula (II'), when m'=1, L _I '', L _II '', and L _III '' are each independently H or a C _1-4 alkyl group.

According to the present invention, in formula (II'), when m'=2, there are two structural units as shown in formula (III'), and L _I ", L _II ", L _III " (when they are all bonded binding ends) in the two structural units can be bonded to each other. Optionally, there is only one L _I ", L _II " or L _III " bonded to each other between the two structural units, that is, only one covalent bond is formed between the two different structural units.

According to the present invention, in formula (II'), when m' is greater than 2, there are m' structural units as shown in formula (III'), and L _I ", L _II ", and L _III " in the m' structural units (when they are all bonded binding ends) can be bonded to each other. Further optionally, the m' structural units are a structural unit at one end, (m'-2) middle structural units and a structural unit at another end that are bonded in sequence, and there is only one L _I ", L _II " or L _III " in the structural unit at each end that is bonded to L _I ", L _II " or L _III " in the adjacent middle structural unit, and there are two L _I ", L _II " or L _III " in each middle structural unit that are respectively bonded to L _I ", L _II " or L _III " in the adjacent structural unit, that is, only one covalent bond is formed between every two connected different structural units.

According to the present invention, examples of the compound represented by formula (II') include:

According to the present invention, preferably, the mass ratio between the ester compound and the optional amine compound is 1:0.1-5, more preferably 1:0.2-3.

The antioxidant composition of the present invention can significantly improve the oxidation stability and high temperature corrosion resistance of lubricating oil, especially synthetic lubricating oil, and is particularly suitable for aviation synthetic ester lubricating oil.

According to the present invention, the method for preparing the ester compound comprises the steps of reacting a compound represented by formula (X) with a compound represented by formula (Y);

In formula (X), n is an integer between 1 and 10, preferably an integer between 1 and 5, and more preferably an integer between 1 and 3; _R0 is selected from n-valent _C1-30 straight or branched alkyl, _C2-30 straight or branched heteroalkyl, preferably selected from n-valent _C1-20 straight or branched alkyl, _C2-20 straight or branched heteroalkyl, more preferably selected from n-valent _C1-10 straight or branched alkyl, _C2-10 straight or branched heteroalkyl; each R' group is independently selected from _C1-10 straight or branched alkylene, preferably selected from _C1-5 straight or branched alkylene, more preferably selected from _C1-3 straight or branched alkylene; each R" group is independently selected from _C1-30 straight or branched alkyl, preferably selected from _C1-20 straight or branched alkyl, more preferably selected from _C1-10 straight or branched alkyl; each R"' group is independently selected from C _{1 to 30} straight or branched chain alkyl groups, preferably selected from C _{1 to 20} straight or branched chain alkyl groups, more preferably selected from C _{1 to 10} straight or branched chain alkyl groups;

In formula (Y), each R _I group is independently selected from H, C _1-10 straight chain or branched alkyl, preferably selected from H, C _1-5 straight chain or branched alkyl, more preferably selected from H, C _1-3 straight chain or branched alkyl; each x is independently selected from an integer between 0 and 4, preferably an integer between 0 and 2, more preferably 0 or 1; each R _II group is independently selected from H, C _1-10 straight chain or branched alkyl, preferably selected from H, C _1-5 straight chain or branched alkyl, more preferably selected from H, C _1-3 straight chain or branched alkyl; each y is independently selected from an integer between 0 and 2, preferably 0 or 1; each R _III group is independently selected from H, C _1-10 straight chain or branched alkyl, preferably selected from H, C _1-5 straight chain or branched alkyl, more preferably selected from H, C _1-3 straight chain or branched alkyl; each z is independently selected from an integer between 0 and 3, preferably an integer between 0 and 2, more preferably 0 or 1.

According to the present invention, the mass ratio between the compound represented by formula (X) and the compound represented by formula (Y) is preferably 1:0.1-5, more preferably 1:0.3-3; the temperature at which the compound represented by formula (X) reacts with the compound represented by formula (Y) is preferably 110-200°C, more preferably 130-190°C; the absolute pressure at which the compound represented by formula (X) reacts with the compound represented by formula (Y) is not particularly limited, and is generally preferably 0.01Mpa-0.15Mpa, more preferably 0.01Mpa-0.12Mpa.

According to the present invention, the reaction time of the compound represented by formula (X) and the compound represented by formula (Y) is preferably as long as possible so that the reaction proceeds smoothly, and is generally preferably 3 to 12 hours, and more preferably 4 to 10 hours.

According to the present invention, the compound represented by formula (X) is preferably selected from the esterification products of _C1-18 monohydric alcohol and/or polyhydric alcohol and _C3-20 fatty acid, the _C1-18 polyhydric alcohol includes one or more of ethylene glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol, and the _C3-20 fatty acid includes one or more of valeric acid, isovaleric acid, hexanoic acid, heptanoic acid, octanoic acid, isooctanoic acid, 2-ethylhexanoic acid, nonanoic acid, 3,5,5-trimethylhexanoic acid, capric acid, lauric acid, palmitic acid and oleic acid.

According to the present invention, the compound represented by formula (X) is more preferably an esterification product of one or more of trimethylolpropane, pentaerythritol, and dipentaerythritol with a C _3-20 saturated fatty acid, and further preferably one or more of trimethylolpropane ester, pentaerythritol ester, and dipentaerythritol ester having a kinematic viscosity at 100° C. in the range of (3.6-4.3) mm ² /s.

According to the present invention, examples of the compound represented by formula (X) include one or more of the following structural compounds:

The definitions of the groups are the same as those in any of the above aspects.

According to the present invention, preferably, the compound represented by formula (X) can be selected from one or more of the following compounds: saturated trimethylolpropane acid ester, saturated pentaerythritol acid ester, saturated dipentaerythritol acid ester, and isooctyl didecanoate.

According to the present invention, preferably, in the compound represented by formula (Y), there is at least one hydrogen atom in the ortho position of each benzene ring to which the amine group is attached.

According to the present invention, preferably, the compound represented by formula (Y) can be selected from one or more of the following compounds: p-tert-butyl-phenyl-1-naphthylamine, p-tert-octyl-phenyl-1-naphthylamine, p-phenethyl-phenyl-1-naphthylamine, phenyl-1-naphthylamine.

According to the present invention, preferably, the compound represented by formula (X) reacts with the compound represented by formula (Y) in the presence of a peroxide. The peroxide is preferably an organic peroxide. The organic peroxide may be one or more of an alkyl peroxide, an acyl peroxide, a peroxyketal and a peroxy organic ester.

The structure of the alkyl peroxide is: R ₁ -OOR ₂

The structure of acyl peroxide is:

The structure of peroxyketal is:

The structure of organic peroxide is:

Each R ₁ and R ₂ group is independently one or more of an alkyl group with a total carbon number of 2-10, an aromatic group, an alkyl substituted aromatic group or an aromatic substituted alkyl group, preferably an alkyl group with a total carbon number of 4-6 and/or a phenyl group, and most preferably a tert-butyl group and/or a phenyl group.

According to the present invention, the organic peroxide is preferably one or more of organic peroxyester tert-butyl-2-ethyl peroxyhexanoate, peroxyketal 2,2-bis(tert-butylperoxide)butane, di-tert-butyl peroxide, dihexyl peroxide and diphenyl peroxide, most preferably di-tert-butyl peroxide.

According to the present invention, the amount of the peroxide is preferably 0.8 to 1.5 times the amount of the compound represented by (Y).

According to the present invention, the reaction of the compound represented by formula (X) and the compound represented by formula (Y) is preferably carried out under the protection of an inert gas, and the inert gas is preferably nitrogen.

According to the present invention, a solvent may or may not be added during the reaction of the compound represented by formula (X) with the compound represented by formula (Y). The solvent is preferably a C ₆ -C ₂₀ alkane, most preferably a C ₆ -C ₁₀ alkane, such as n-decane, n-heptane, cyclohexane.

According to the present invention, the reaction product of the compound represented by formula (X) and the compound represented by formula (Y) can be a single ester compound, or a mixture of multiple ester compounds, or a mixture of one or more ester compounds and the compound represented by formula (II') described in the second aspect, or a mixture of one or more ester compounds and the compound represented by formula (II') described in the second aspect and the compound represented by formula (X).

According to the present invention, the reaction product of the compound shown in formula (X) and the compound shown in formula (Y) can be a single ester compound or a mixture of multiple ester compounds. These reaction products are all expected by the present invention, and the difference in their existence forms does not affect the realization of the effect of the present invention. Therefore, in the context of this specification, these reaction products are all collectively referred to as the ester compounds without distinction. In view of this, according to the present invention, there is no absolute necessity to further purify the reaction product or to further separate an ester compound of a specific structure from the reaction product. Of course, the purification or separation is preferred for further improving the expected effect of the present invention, but it is not necessary for the present invention. Nevertheless, as the purification or separation method, for example, purification or separation of the reaction product by column chromatography or preparative chromatography can be cited.

According to the present invention, the reaction product of the compound represented by formula (X) and the compound represented by formula (Y) can be a mixture of one or more ester compounds and the compound represented by formula (II') described in the second aspect, and the mixture is the antioxidant composition described in the second aspect of the present invention. In addition to reacting with the compound represented by formula (X), the compound represented by formula (Y) can also undergo a coupling reaction between its own molecules during the reaction process, and the coupling product between its own molecules is the compound represented by formula (II') in which m is greater than 1. Therefore, the compound represented by formula (II') includes the unreacted compound represented by formula (Y) (that is, the compound represented by formula (II') in which m is equal to 1) and the coupling product between the compound represented by formula (Y) itself (that is, the compound represented by formula (II') in which m is greater than 1).

According to the present invention, when the reaction product of the compound represented by formula (X) and the compound represented by formula (Y) is a mixture of one or more ester compounds and the compound represented by formula (II') described in the second aspect, the compound represented by formula (II') described in the second aspect can be separated; or the compound represented by formula (II') described in the second aspect can be used directly as the antioxidant composition of the present invention without being separated.

According to the present invention, the reaction product of the compound represented by formula (X) and the compound represented by formula (Y) can be a mixture of one or more ester compounds and the compound represented by formula (II') described in the second aspect and the compound represented by formula (X). The reaction product may contain the compound represented by formula (X), that is, the unreacted compound represented by formula (X).

According to the present invention, when the reaction product of the compound represented by formula (X) and the compound represented by formula (Y) is a mixture of one or more ester compounds and the compound represented by formula (II') and the compound represented by formula (X) described in the second aspect, the compound represented by formula (X) can be separated out; or the compound represented by formula (X) can be used as an additional component without being separated out. Because the compound represented by formula (X) itself is an ester compound, it can be used as a lubricating base oil or an anti-wear agent or a friction modifier, and therefore can be used as an additional component.

According to the present invention, in the reaction of the compound represented by formula (X) with the compound represented by formula (Y), the reaction product can be purified to improve the purity of the reaction product. Examples of purification methods include washing, recrystallization, etc., and there is no particular limitation.

In a second aspect, the present invention provides a method for preparing the antioxidant composition.

The preparation method of the antioxidant composition comprises the step of mixing the ester compound, the multifunctional oiliness agent and the optional amine compound.

In a third aspect, the present invention provides a lubricating oil composition.

The lubricating oil composition of the present invention comprises a lubricating base oil and an antioxidant composition as described in any one of the above aspects. The antioxidant composition as described in any one of the above aspects accounts for 1% to 20% of the total mass of the lubricating oil composition, preferably 3% to 15% of the total mass of the lubricating oil composition. The lubricating base oil is preferably a synthetic hydrocarbon and/or a synthetic ester, more preferably an ester formed by the reaction of a C _1-10 polyol and a C _3-20 fatty acid. Examples of the C _1-10 polyol include one or more of trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol. Examples of the C _3-20 fatty acid include one or more of valeric acid, isovaleric acid, hexanoic acid, heptanoic acid, octanoic acid, isooctanoic acid, 2-ethylhexanoic acid, nonanoic acid, 3,5,5-trimethylhexanoic acid, capric acid and lauric acid. The lubricating base oil is more preferably an esterification product of one or more of trimethylolpropane, pentaerythritol, and dipentaerythritol with a saturated fatty acid of _{3 to 20} carbon atoms, and further preferably one or more of trimethylolpropane ester, pentaerythritol ester, and dipentaerythritol ester having a kinematic viscosity of (3 to 12) mm ² /s at 100°C. Other additives may also be added to the lubricating oil composition of the present invention, such as a viscosity index improver, an anti-wear agent, a pour point depressant, a rust inhibitor, etc.

The lubricating oil composition of the present invention has excellent oxidation stability and high temperature corrosion resistance.

In a fourth aspect, the present invention further provides a method for improving the anti-oxidation and anti-corrosion performance of a lubricating oil composition, the method comprising adding the antioxidant composition described in any of the above aspects into a lubricating base oil.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is an overlay spectrum of the reaction raw material p-tert-octyl-phenyl-1-naphthylamine (L06) and the reaction product A1.

FIG. 2 is an infrared spectrum of the reaction product B1 (ie, liquid alkylbenzotriazole fatty amine salt).

FIG3 is a NMR spectrum of the reaction product B1 (i.e., liquid alkylbenzotriazole fatty amine salt).

DETAILED DESCRIPTION

In the context of this specification, the expression "number + valence + group" or similar expressions refers to a group obtained by removing the number of hydrogen atoms represented by the number from the basic structure (such as a chain, a ring or a combination thereof) corresponding to the group, preferably refers to a group obtained by removing the number of hydrogen atoms represented by the number from the carbon atoms (preferably saturated carbon atoms and/or non-same carbon atoms) contained in the structure. For example, "trivalent straight or branched alkyl" refers to a group obtained by removing 3 hydrogen atoms from a straight or branched alkane (i.e., the basic chain corresponding to the straight or branched alkyl), while "divalent straight or branched heteroalkyl" refers to a group obtained by removing 2 hydrogen atoms from a straight or branched heteroalkane (preferably from carbon atoms contained in the heteroalkane, or further, from non-same carbon atoms).

In the context of this specification, the heteroalkyl group refers to a group obtained by interrupting the carbon chain structure of the alkyl group by one or more (such as 1 to 5, 1 to 4, 1 to 3, 1 to 2 or 1) hetero groups selected from -Sx-, -O- and -NR""-, wherein x is an integer between 1 and 5 (preferably an integer between 1 and 4, more preferably 1, 2 or 3). From the perspective of structural stability, preferably, when there are multiple hetero groups, any two of the hetero groups are not directly bonded. Obviously, the hetero group is not at the end of the carbon chain of the hydrocarbon group. For the sake of convenience of expression, the number of carbon atoms of the alkyl group before the interruption is still used to refer to the number of carbon atoms of the heteroalkyl group after the interruption. For example, a C ₄ straight-chain alkyl group (CH ₃ -CH ₂ -CH ₂ -CH ₂ -) interrupted by one hetero group -O- can obtain C 4 straight-chain heteroalkyl groups such as CH ₃ -CH ₂ -CH ₂ -CH ₂ -, CH ₃ -CH ₂ -O-CH ₂ -CH ₂ -, or CH ₃ -CH ₂ -CH ₂ -O-CH ₂ -; interrupted by two hetero groups -S- can obtain C ₄ straight-chain heteroalkyl groups such as CH ₃ -S-CH ₂ -S-CH ₂ -CH ₂ -, CH ₃ -CH ₂ -S-CH ₂ -S-CH ₂ -, or CH ₃ -S-CH ₂ -CH ₂ -S-CH ₂ -; and interrupted by three hetero groups -S- can obtain C ₄ straight-chain heteroalkyl groups such as _{CH 3} -S-CH ₂ -S-CH ₂ -S-CH ₂ -.

Unless otherwise stated, the percentages and ratios mentioned below are by mass percentage or mass ratio.

The main raw materials used are as follows:

Antioxidant L06, p-tert-octyl-phenyl-1-naphthylamine, BASF, purity > 98%

VANLUBEV81, Vanderbilt Corporation, USA, purity＞98％

5-Methylbenzotriazole, Shanghai Chemical Plant, chemically pure

C ₁₆ ～C ₂₂ alkyl primary amine monomer, purity> 97%, purchased from Institute of Chemistry, Chinese Academy of Sciences

Antioxidant T534, antioxidant alkyl diphenylamine, Petrochemical Research Institute Xingpu Company

Antioxidant T501, 2,6-di-tert-butyl-4-methylphenol, Lianyungang Ningkang Chemical Co., Ltd.

Antioxidant T558, dinonyldiphenylamine, Liaoning Tianhe Fine Chemical Co., Ltd.

Antioxidant T531, N-phenyl-1-naphthylamine, Tianjin Maofeng Chemical Co., Ltd.

Pentaerythritol ester, Zhejiang Quzhou Chemical Co., Ltd., kinematic viscosity at 100℃ is ^5.02mm2 /s.

Tetracentis polyol saturated acid ester, Shandong Ruijie Chemical Co., Ltd., kinematic viscosity at 100℃ is ^3.82mm2 /s.

Trimethylolpropane ester, Sinopec Great Wall Lubricant Chongqing Branch, product code Great Wall 5101 high temperature synthetic lubricant, 100℃ kinematic viscosity is ^5.05mm2 /s.

Dipentaerythritol ester, Shandong Ruijie Chemical Co., Ltd., kinematic viscosity at 100℃ is ^7.0mm2 /s.

Di-tert-butyl peroxide, Jiangsu Qiangsheng Functional Chemical Co., Ltd., chemically pure.

Example 1

90g of raw material p-tert-octyl-phenyl-1-naphthylamine was added to 90g of 100℃ kinematic viscosity was ^3.85mm2 /s of four centistokes trimethylolpropane ester, the mixed system is heated, stirred and dissolved in the presence of nitrogen, the mixed system is maintained at 145°C, 65g of di-tert-butyl peroxide is added to the reaction system, and the reaction is carried out at a constant temperature of 145°C±2°C for 4h, and then the vacuum distillation is carried out at 145°C±2°C and ≤1000Pa for 30min, and then the vacuum degree is increased to ≤500Pa, and the temperature is gradually increased to and maintained at 175°C for vacuum distillation for more than 40min. After the vacuum distillation is completed, the product is cooled in a nitrogen environment to finally obtain 168g of reaction product A1, which mainly contains compounds of structural formula P-1, structural formula P-2 and structural formula P-3, and also contains relatively small amounts of compounds of structural formula (II'-1), structural formula (II'-2), structural formula (II'-3) and structural formula (II'-4), as well as a small amount of trimethylolpropane ester used in this embodiment.

Prepare a glacial acetic acid solution with a mass concentration of 90%. Add 0.3 mol (35.7 g) of methylbenzotriazole and 0.2 mol (64.6 g) of alkyl primary amine into a three-necked flask in sequence, and stir and heat. The composition of the alkyl primary amine is as follows: based on the total molar amount of the alkyl primary amine, the molar percentage of _C16 - _C18 primary amine is 65% in total, and the molar percentage of _C19 - _C20 primary amine is 35% in total, wherein the molar percentage of _C16 - _C18 and _C19 - _C20 straight-chain primary amines is 50% and 20% in sequence, and the molar percentage of _C16 - _C18 and _C19 - _C20 branched primary amines is 15% and 15% in sequence. When the temperature of the reaction mixture reaches 85°C, 20g of 90% acetic acid solution is added dropwise to the three-necked flask for 15min, and the reaction is carried out at 80°C to 85°C for 5h. After the reaction is completed, the upper layer of the liquid reaction product is washed with 80°C distilled water until it is neutral. After the mixed solution is shaken, allowed to stand, cooled, and separated, the upper layer of the liquid is subjected to temperature-controlled reduced-pressure vacuum distillation to obtain 80g of a completely transparent and bright orange liquid reaction product, which is the multifunctional oiliness agent B1.

The reaction product A1 and the reaction product B1 were uniformly stirred at a mass ratio of 40:1 at a temperature below 80° C. to prepare an antioxidant composition C1.

The reaction raw material p-tert-octyl-phenyl-1-naphthylamine (L06) and the reaction product A1 were characterized by infrared analysis, and the superimposed spectra of the two are shown in Figure 1.

The peak data in Figure 1 are tabulated below.

Statistical comparison table of infrared spectrum absorption peaks of reaction raw materials and reaction products

Combined with Figure 1 and the above table, a spectrum analysis was performed, as follows:

The reaction raw material (L06) has 35 typical absorption peaks; the reaction product (L06-2 polymer) has 17 typical absorption peaks. By comparison, the number of infrared absorption peaks has been significantly reduced; the strong infrared absorption peak of the secondary amino group at 3412 cm ^-1 has been significantly weakened, which is consistent with the typical characteristics of the infrared spectrum of the polymer and the infrared spectrum absorption peaks of its monomer compounds, indicating that oligomerization has indeed occurred and the corresponding oligomers have been generated.

The infrared absorption peak band of the reaction raw material (2956.1～2866.32) cm ^-1 is obviously wider and blunter, and the infrared absorption peak band corresponding to the reaction product is (2957.1～2863.2) cm ^-1 ; the absorption peaks of 1586 cm ^-1 (medium intensity) and 1464 cm ^-1 (medium intensity) in the reaction product are typical aromatic ring ν _C＝C characteristic absorption peaks, and it is determined that the main structure in the reaction product is an aromatic secondary amine structure;

The absorption peaks of 1614 cm ^-1 (medium intensity), 1578 cm ^-1 (medium intensity), and 1477 cm ^-1 in the reaction raw material L06 are typical benzene ring ν _C＝C characteristic absorption peaks in the aromatic secondary amine structure; by comparing the peak of 1586 cm ^-1 of the reaction product with the peak of 1578 cm ^-1 of the reaction raw material, it can be seen that the intensity of the key characteristic peaks of the reaction product is relatively low. Similarly, by comparing the peak of 827 cm ^-1 of the reaction product with the peak of 823 cm ^-1 of the reaction raw material, it can be seen that the intensity of the key characteristic peaks of the reaction product is relatively low.

The absorption peak band (1465～1610) cm ^-1 is an important feature of the infrared spectrum of aromatic compounds. The infrared absorption peak of the reaction product at 1586 cm ^-1 is significantly weaker than the infrared absorption peaks of the reaction raw materials at 1614 cm ^-1 and 1578 cm ^-1. The difference in the absorption band morphology between the raw materials and the products here is the reason for the existence of multiple aromatic rings in the reaction product, which also proves that the reaction raw materials undergo oligomerization to form oligomeric compounds with multiple aromatic rings. The presence of a large number of aromatic secondary amines in the reaction product confirms that the alkylated aromatic amine undergoes oligomerization by aromatic ring free radical substitution.

In the infrared spectrum of the reaction product, there is a strong absorption peak at 1745.94 cm ^-1 which is typical of ester groups, indicating that there are ester groups in the chemical structure of the synthetic product A1.

The reaction product B1 was sampled and characterized by infrared analysis. The infrared spectrum is shown in Figure 2.

As can be seen from Figure 2, 1628.47cm ^-1 is a typical δ _as (NH ₃ ⁺ ) characteristic absorption peak, 1546.05cm ^-1 is a typical δ _s (NH ₃ ⁺ ) characteristic absorption peak, 2958.96~2164.40cm ^-1 is a typical ν _NH (NH ₃ ⁺ ) wider and stronger absorption band, especially around 2591cm ^-1 and 2729cm ^-1 , there is obvious absorption of ν _NH (NH ₃ ⁺ ), and the spectrum proves that the reaction product contains a large amount of primary amine salts; 1623.26cm ^-1 , 1595.28cm ^-1 , 1508.09cm ^-1 are characteristic absorption peaks of ν _C＝C , 3071.48cm ^-1 is the characteristic absorption peak of ν _＝CH on the benzene ring, from which it can be judged that there is a benzene ring; 1280.26cm ^-1 is a typical characteristic absorption peak of ν _CN of aromatic primary amines; and at 3500cm -1, There is no characteristic absorption peak of hydrogen ν _NH on the nitrogen at the 1-position of benzotriazole near ^-1 , and the spectrum confirms that there is no primary amine in the liquid product, indicating that benzotriazole reacts to generate benzotriazole alkyl fatty amine salt.

The reaction product B1 was sampled and characterized by ¹ H NMR analysis. The NMR spectrum is shown in Figure 3.

As shown in Figure 3, the ^1HNMR spectrum of the liquid product alkylbenzenetriazole fatty amine salt has a new hydrogen proton chemical shift signal peak at δ3.198. This signal peak does not exist in the ^1HNMR spectrum of benzotriazole and the ^1HNMR spectrum of alkyl fatty acid ammonium. This signal peak is generated by the chemical shift of α-H on the methylene adjacent to the primary amine salt. Based on this, it is judged that the reaction product contains a primary amine salt with hydrogen protons. δ1.152~δ1.245 and δ0.977~δ1.108 in the ^1HNMR spectrum represent the methyl and methylene hydrogen proton chemical shift signal peaks on the alkyl chain of the reaction product, respectively.

By analyzing the ¹ HNMR spectrum of the liquid alkylbenzotriazole fatty amine salt, it can be found that the chemical shift band δ12~δ15 (δ13.859) on the spectrum disappears, indicating that the chemical shift signal of the active hydrogen proton on the -NH- of benzotriazole disappears, and the active hydrogen on the nitrogen at position 1 of benzotriazole undergoes a chemical reaction to generate the liquid alkylbenzotriazole fatty amine salt of the present invention.

Example 2

90g of raw material p-tert-octyl-phenyl-1-naphthylamine was added to 90g of 100℃ kinematic viscosity was ^5.02mm2 /s of pentaerythritol ester, the mixed system is heated, stirred and dissolved in the presence of nitrogen, the mixed system is maintained at 140°C, 65g of di-tert-butyl peroxide is added to the reaction system, the reaction is carried out at 140°C±2°C for 3h, and then vacuum distillation is carried out at 140°C±2°C and ≤1000Pa for 30min, the vacuum degree is increased to ≤500Pa, and the temperature is gradually increased and maintained at 175°C for vacuum distillation for more than 40min. After the vacuum distillation is completed, the product is cooled in a nitrogen environment to finally obtain 165g of reaction product A2, which mainly comprises compounds with similar structures to structural formula P-1, structural formula P-2 and structural formula P-3 (the difference is that the ester group therein is the ester group of pentaerythritol ester), and also comprises a relatively small amount of compounds of structural formula (II'-1), structural formula (II'-2), structural formula (II'-3) and structural formula (II'-4), as well as a small amount of pentaerythritol ester used in this embodiment.

Prepare a glacial acetic acid solution with a mass concentration of 90%. Add 0.3 mol (35.7 g) of methylbenzotriazole and 0.1 mol (64.6 g) of alkyl primary amine into a three-necked flask in sequence, and stir and heat. The alkyl primary amine composition is as follows: based on the total molar amount of the alkyl primary amine, the molar percentage of _C16 - _C18 primary amine is 65% in total, and the molar percentage of _C19 - _C20 primary amine is 35% in total, wherein the molar percentage of _C16 - _C18 and _C19 - _C20 straight-chain primary amines is 45% and 25% in sequence; the molar percentage of _C16 - _C18 and _C19 - _C20 branched primary amines is 20% and 10% in sequence. When the temperature of the reaction mixture reaches 85°C, 20g of 90% acetic acid solution is added dropwise to the three-necked flask for 20min, and the reaction is carried out at 80°C to 85°C for 5h. After the reaction is completed, the upper layer of the liquid reaction product is washed with 80°C distilled water until it is neutral. After the mixed solution is allowed to stand and stratified, the upper layer of the liquid is subjected to temperature-controlled reduced-pressure vacuum distillation to obtain 77.5g of a completely transparent bright orange liquid reaction product, which is the multifunctional oiliness agent B2;

The reaction product A2 and the reaction product B2 were uniformly stirred at a mass ratio of 40:1 at a temperature below 80° C. to prepare an antioxidant composition C2.

Example 3

130 g of the raw material p-tert-octyl-phenyl-1-naphthylamine was added to 150 g of pentaerythritol ester with a kinematic viscosity of 4.6 mm ² /s at 100° C., and the mixed system was heated and stirred under a nitrogen environment to maintain the system temperature at 140° C.±2° C. 80 g of di-tert-butyl peroxide was added to the reaction system, and the reaction was carried out at 150° C.±2° C. for 3 h, and then the reaction was distilled under reduced pressure at 150° C.±2° C. and ≤1000 Pa for more than 40 min. After the distillation was completed, the product was cooled under a nitrogen environment to finally obtain 270 g of reaction product A2. The reaction product A2 mainly contained compounds with similar structures to those of formula P-1, formula P-2, and formula P-3 (the difference being that the ester groups therein were the ester groups of pentaerythritol ester), and also contained relatively small amounts of compounds of formula (II'-1), formula (II'-2), formula (II'-3), and formula (II'-4), and a small amount of pentaerythritol ester in this embodiment.

Prepare a 90% glacial acetic acid solution. Add 0.15 mol (17.85 g) of methylbenzotriazole and 0.1 mol (32.3 g) of alkyl primary amine to a three-necked flask, and stir and heat. The composition of the alkyl primary amine is as follows: based on the total molar amount of the alkyl primary amine, the molar percentage of C ₁₆ ～ C ₁₈ and C ₁₉ ～ C ₂₀ straight-chain primary amines is 40% and 25% respectively; the molar percentage of C ₁₆ ～ C ₁₈ and C ₁₉ ～ C ₂₀ branched primary amines is 25% and 10% respectively. When the temperature of the reaction mixture reaches 75°C, start to drop 20 g of 90% acetic acid solution into the three-necked flask. The drop time is 15 minutes. The reaction is carried out at 70°C to 75°C for 5 hours. After the reaction was completed, the upper layer of the liquid reaction product was washed with 70°C distilled water until it was neutral. After the mixed solution was allowed to stand and separate, the upper layer of the liquid was subjected to temperature-controlled reduced-pressure vacuum distillation to obtain 36.27 g of a completely transparent bright orange liquid reaction product, which was the multifunctional oiliness agent B3.

The reaction product A3 and the reaction product B3 were uniformly stirred at a mass ratio of 40:1 at a temperature below 80° C. to prepare an antioxidant composition C3.

Example 4

150g of raw material p-tert-octyl-phenyl-1-naphthylamine was added to 150g of mixed polyol saturated acid ester (wherein the mass ratio of trimethylolpropane ester to dipentaerythritol ester was 3:1), the mixed system was heated, stirred and dissolved in the presence of nitrogen, and the mixed system was maintained at 150°C±2°C. 90g of di-tert-butyl peroxide was added to the reaction system, and the reaction was carried out at 150°C for 4h, and then vacuum distillation was carried out at 150°C±2°C and ≤1000Pa for more than 40min. After the vacuum distillation was completed, the product was The reaction product A4 was cooled under a nitrogen environment to obtain 286 g of reaction product A4. The reaction product A4 mainly contained compounds with structures similar to those of formula P-1, formula P-2, and formula P-3 (the difference being that the ester groups therein are ester groups of mixed polyol saturated acid esters), and also contained relatively small amounts of compounds of formula (II'-1), formula (II'-2), formula (II'-3), and formula (II'-4), as well as a small amount of mixed polyol saturated acid esters used in this embodiment.

The reaction product A4 and the reaction product B2 (prepared in Example 2) were uniformly stirred at a mass ratio of 40:1 at a temperature below 80° C. to prepare an antioxidant composition C4.

Oxidation stability and high temperature corrosion resistance evaluation

The reaction products or compositions C1-C4 of the present invention and comparative antioxidants V81, T558, T534, T531 and tricresol phosphate (TCP) were added to a pentaerythritol saturated acid ester lubricating base oil with a kinematic viscosity of 5.02 ^mm2 /s at 100°C, and heated and stirred to prepare lubricating oil compositions of Examples 5-12 and Comparative Examples 1-4. The formulation compositions of lubricating oil compositions of Examples 5-8 and Comparative Examples 1-4 of the present invention are shown in Table 1.

High temperature corrosion and oxidation stability assessment

The lubricating oil compositions in Table 1 were subjected to corrosion and oxidation stability assessment tests respectively, and the test method used was the method FEDSTD-791-5308 specified by the international oil specification MIL-PRF-23699G. The experimental conditions were: dry air was introduced for oxidation at a constant temperature of 204°C for 72 hours; the oxygen flow rate was 50-83 mL/min; the metal test pieces were steel, silver, titanium (copper) aluminum, and titanium (magnesium) of specific specifications, and the changes in the total acid value of the lubricating oil at 25°C, the viscosity change rate at 40°C, and the amount of oil deposits formed in 100 mL before and after oxidation were examined.

The evaluation indexes of the method are: the change of total acid value before and after oxidation of the oil sample (△TAN/mgKOH·g ^-1 ); the change rate of viscosity at 40℃ (△Viscosity%); the amount of sediment generated in 100mL test oil sample (Deposit/mg·(100mL) ^-1 ); the mass change per unit area of metal test pieces such as copper, steel, silver, aluminum, and titanium. The present invention evaluates the experimental results based on the mass change data of the copper piece. The test results are shown in Table 2.

Table 1 Examples 5-8 and Comparative Examples 1-4 of the lubricating oil compositions

Comparing the technical index requirements of the FED-STD-791-5308 and GJB563 method evaluation methods with the corrosion and oxidation stability evaluation data results in Table 2, it can be seen that the 5 centistoke level lubricating oil composition Examples 5-8 to which the antioxidant composition of the present invention is added have significant advantages over the lubricating oil composition of the comparative example in terms of metal sheet mass change, total acid value change, viscosity change rate, and deposit generation, and meet the technical index requirements of corrosion and oxidation stability of the FED-STD-791-5308 and GJB563 methods. It can be seen that the antioxidant composition of the present invention has excellent high-temperature antioxidant performance and anti-deposit generation performance, can better control the total acid value change, viscosity change rate, and deposit generation of the lubricating oil before and after oxidation, and well meets the corrosion and oxidation stability index requirements of the FED-STD-791-5308 and GJB563 methods.

Table 2 High temperature corrosion and oxidation stability assessment test results

Claims (29)

1. An antioxidant composition comprises an ester compound and a multifunctional oiliness agent, wherein the structure of the ester compound is shown as a formula (I):

in the formula (I), n is an integer between 1 and 10; r ₀ is selected from the group consisting of n-valent C _1～30 linear or branched alkyl, C _2～30 linear or branched heteroalkyl; each R' group is independently selected from C _1～10 straight or branched chain alkylene; each R "group is independently selected from C _1～30 straight or branched alkyl; each R' "group is independently selected from C _1～30 straight or branched alkyl; each A group is selected from a 1-valent group shown in a formula (II), H, C _1～20 is a straight chain or branched chain alkyl group, and at least one A group in the formula (I) is selected from a 1-valent group shown in the formula (II);

The formula (II) is a 1-valent group formed by bonding m structural units shown in the formula (III),

In the formula (II), m is an integer between 1 and 10; each R _I group is independently selected from H, C _1～10 straight or branched alkyl; each x is independently selected from integers between 0 and 4; each R _II group is independently selected from H, C _1～10 straight or branched alkyl; each y is independently selected from integers between 0 and 2; each R _III group is independently selected from H, C _1～10 straight or branched alkyl; each z is independently selected from integers between 0 and 3;

Each L _I、L_II、L_III in formula (II) is independently H, C _1～4 alkyl, a binding end bonded to L _I、L_II、L_III in a different building block, a binding end bonded to formula (I), a 1-valent group represented by formula (IV); only one L _I、L_II or L _III present in formula (II) is a binding end that is bonded to formula (I);

Delta in the 1-valent group represented by the formula (IV) represents a binding end bonded to L _I、L_II or L _III;

In the formula (IV), n' is an integer between 1 and 10; r ₀ is selected from the group consisting of n-valent C _1～30 linear or branched alkyl, C _2～30 linear or branched heteroalkyl; each R' group is independently selected from C _1～10 straight or branched chain alkylene; each R "group is independently selected from C _1～30 straight or branched alkyl; each R' "group is independently selected from C _1～30 straight or branched alkyl;

The preparation method of the multifunctional oiliness agent comprises the following steps: in the presence of inert gas, alkyl benzotriazole and/or benzotriazole and alkyl primary amine react under the action of an acid catalyst, and the product is collected.

2. The antioxidant composition according to claim 1, wherein in formula (I), n is an integer between 1 and 5; r ₀ is selected from the group consisting of n-valent C _1～20 linear or branched alkyl, C _2～20 linear or branched heteroalkyl; each R' group is independently selected from C _1～5 straight or branched chain alkylene; Each R "group is independently selected from C _1～20 straight or branched alkyl; each R' "group is independently selected from C _1～20 straight or branched alkyl; each A group is selected from the group shown in formula (II), H, C _1～10 straight-chain or branched alkyl; In the formula (II), m is an integer between 1 and 5; each R _I group is independently selected from H, C _1～5 straight or branched alkyl; each x is independently selected from integers between 0 and 2; each R _II group is independently selected from H, C _1～5 straight or branched alkyl; Each y is independently selected from 0 or 1; each R _III group is independently selected from H, C _1～5 straight or branched alkyl; each z is independently selected from integers between 0 and 2; in the formula (IV), n' is an integer between 1 and 5; r ₀ is selected from the group consisting of n-valent C _1～20 linear or branched alkyl, C _2～20 linear or branched heteroalkyl; Each R' group is independently selected from C _1～5 straight or branched alkylene; each R "group is independently selected from C _1～20 straight or branched alkyl; each R' "group is independently selected from C _1～20 straight or branched alkyl.

3. The antioxidant composition according to claim 2, wherein in formula (I), n is an integer between 1 and 3; r ₀ is selected from the group consisting of n-valent C _1～10 linear or branched alkyl, C _2～10 linear or branched heteroalkyl; each R' group is independently selected from C _1～3 straight or branched chain alkylene; Each R "group is independently selected from C _1～10 straight or branched alkyl; each R' "group is independently selected from C _1～10 straight or branched alkyl; each A group is selected from the group shown in formula (II), H, C _1～5 straight-chain or branched alkyl; In the formula (II), m is an integer between 1 and 3; each R _I group is independently selected from H, C _1～3 straight or branched alkyl; each x is independently selected from 0 or 1; each R _II group is independently selected from H, C _1～3 straight or branched alkyl; Each R _III group is independently selected from H, C _1～3 straight or branched alkyl; each z is independently selected from 0 or 1; in the formula (IV), n' is an integer between 1 and 3; r ₀ is selected from the group consisting of n-valent C _1～10 linear or branched alkyl, C _2～10 linear or branched heteroalkyl; Each R' group is independently selected from C _1～3 straight or branched chain alkylene; each R "group is independently selected from C _1～10 straight or branched alkyl; each R' "group is independently selected from C _1～10 straight or branched alkyl.

4. The antioxidant composition as claimed in claim 1, wherein,

In formula (II), when m=1, one of L _I、L_II、L_III is a binding end bonded to formula (I), and the other two are each independently H, C _1～4 alkyl or a 1-valent group represented by formula (IV);

in formula (II), when m=2, there are 2 structural units represented by formula (III), and only one L _I、L_II or L _III each exists between the 2 structural units;

In formula (II), when m is greater than 2, there are m structural units as shown in formula (III), m structural units are 1 end structural units, (m-2) intermediate structural units and another 1 end structural unit bonded in this order, only one L _I、L_II or L _III is bonded to L _I、L_II or L _III in the intermediate structural unit adjacent thereto in each end structural unit, and 2L _I、L_II or L _III is bonded to L _I、L_II or L _III in the structural unit adjacent thereto, respectively, in each intermediate structural unit.

5. The antioxidant composition of claim 1, wherein the group of formula (II) comprises:

wherein represents the binding end to the bond of formula (I).

6. The antioxidant composition of claim 1, wherein the ester compound comprises:

The group PAN represents a group represented by formula (II).

7. The antioxidant composition of claim 1, wherein the alkyl benzotriazole and/or benzotriazole has the structure:

Wherein R ₁' is selected from H, C ₁～C₁₂ straight or branched alkyl;

The primary alkyl amine is C ₁₆～C₂₂ primary alkyl amine, and has a structural formula of R ₂'CH₂NH₂, wherein R ₂' is C ₁₅～C₂₁ straight-chain or branched-chain alkyl;

The acidic catalyst is one or more of glacial acetic acid, sulfuric acid, hydrochloric acid, phosphoric acid, SO ₃ and P ₂O₅ or an aqueous solution of the substances and the mixture thereof.

8. The antioxidant composition of claim 7, wherein R ₁' is selected from the group consisting of C ₁～C₈ straight or branched alkyl.

9. The antioxidant composition of claim 7, wherein R ₁' is selected from methyl.

10. The antioxidant composition of claim 1, wherein the primary alkyl amine is a mixed primary alkyl amine of C ₁₆～C₂₂.

11. The antioxidant composition as set forth in claim 10, wherein,

Based on the total moles of mixed primary alkylamines, the alkyl groups are in mole percent: the mixed primary alkyl amine of C ₁₆～C₂₂ contains 55-90% of the linear primary alkyl amine of C ₁₆～C₂₂ and 10-45% of the branched primary alkyl amine of C ₁₆～C₂₂; or alternatively

Based on the total mole number of the mixed primary alkylamines, the carbon content is calculated in mole percent: the content of C ₁₆～C₁₈ alkyl primary amine in the C ₁₆～C₂₂ mixed alkyl primary amine is 45-85%, and the content of C ₁₉～C₂₂ alkyl primary amine is 15-55%; or alternatively

Based on the total mole number of mixed primary alkylamines, the carbon number and alkyl type are calculated in mole percent: of the mixed alkyl primary amines of C ₁₆～C₂₂, the content of the linear primary amine of C ₁₆～C₁₈ is 40-70%, the content of the linear primary amine of C ₁₉～C₂₂ is 15-40%, the content of the branched primary amine of C ₁₆～C₁₈ is 5-35%, and the content of the branched primary amine of C ₁₉～C₂₂ is 5-30%.

12. The antioxidant composition as set forth in claim 10, wherein,

Based on the total moles of mixed primary alkylamines, the alkyl groups are in mole percent: the mixed alkyl primary amine of C ₁₆～C₂₂ comprises 55-80% of linear alkyl primary amine of C ₁₆～C₂₂ and 20-45% of branched alkyl primary amine of C ₁₆～C₂₂; or alternatively

Based on the total mole number of the mixed primary alkylamines, the carbon content is calculated in mole percent: the content of the C ₁₆～C₁₈ alkyl primary amine in the C ₁₆～C₂₂ mixed alkyl primary amine is 55-75%, and the content of the C ₁₉～C₂₂ alkyl primary amine is 25-45%; or alternatively

Based on the total mole number of mixed primary alkylamines, the carbon number and alkyl type are calculated in mole percent: of the mixed alkyl primary amines of C ₁₆～C₂₂, the content of the linear primary amine of C ₁₆～C₁₈ is 45-60%, the content of the linear primary amine of C ₁₉～C₂₂ is 20-35%, the content of the branched primary amine of C ₁₆～C₁₈ is 5-25%, and the content of the branched primary amine of C ₁₉～C₂₂ is 5-30%.

13. The antioxidant composition according to claim 1, wherein the molar ratio between the alkylbenzene triazole and/or benzotriazole and the primary alkylamine is 1:0.5 to 1; the mass ratio of the acid catalyst to the alkyl benzotriazole and/or the benzotriazole is 1:0.5 to 5; the reaction temperature of the alkyl benzotriazole and/or the benzotriazole and the alkyl primary amine under the action of the acid catalyst is 60-100 ℃.

14. The antioxidant composition of claim 13, wherein the molar ratio between the alkyl benzotriazole and/or benzotriazole and the alkyl primary amine is 1:0.8 to 1; the mass ratio of the acid catalyst to the alkyl benzotriazole and/or the benzotriazole is 1:0.8 to 4; the reaction temperature of the alkyl benzotriazole and/or the benzotriazole and the alkyl primary amine under the action of the acid catalyst is 80-100 ℃.

15. The antioxidant composition according to any one of claims 1 to 14, wherein the mass ratio between the ester compound and the multifunctional oily agent is 10 to 60:1.

16. The antioxidant composition according to any one of claims 1 to 14, wherein the mass ratio between the ester compound and the multifunctional oily agent is 15 to 50:1.

17. The antioxidant composition according to any one of claims 1 to 14, further comprising an amine compound having a structure represented by formula (II'):

The formula (II ') is a compound formed by bonding m ' structural units shown as the formula (III '),

In formula (II '), m' is an integer of 1 to 10; each R _I group is independently selected from H, C _1～10 straight or branched alkyl; each x is independently selected from integers between 0 and 4; each R _II group is independently selected from H, C _1～10 straight or branched alkyl; each y is independently selected from integers between 0 and 2; each R _III group is independently selected from H, C _1～10 straight or branched alkyl; each z is independently selected from integers between 0 and 3;

Each L _I"、L_II"、L_III "in formula (II') is independently H, C _1～4 alkyl, a binding end that binds to L _I"、L_II"、L_III" in a different building block.

18. The antioxidant composition as set forth in claim 17, wherein in the formula (II '), m' is an integer of 1 to 5; each R _I group is independently selected from H, C _1～5 straight or branched alkyl; each x is independently selected from integers between 0 and 2; each R _II group is independently selected from H, C _1～5 straight or branched alkyl; each y is independently selected from 0 or 1; each R _III group is independently selected from H, C _1～5 straight or branched alkyl; each z is independently selected from integers between 0 and 2.

19. The antioxidant composition as set forth in claim 18, wherein in the formula (II '), m' is an integer of 1 to 3; each R _I group is independently selected from H, C _1～3 straight or branched alkyl; each x is independently selected from 0 or 1; each R _II group is independently selected from H, C _1～3 straight or branched alkyl; each R _III group is independently selected from H, C _1～3 straight or branched alkyl; each z is independently selected from 0 or 1.

20. The antioxidant composition of claim 17, wherein,

In formula (II '), when m' =1, each L _I"、L_II"、L_III "is independently H or C _1～4 alkyl; in formula (II '), when m ' =2, there are 2 structural units represented by formula (III '), and only one L _I"、L_II "or L _III" exists between the 2 structural units, respectively, to be bonded to each other;

In the formula (II '), when m' is greater than 2, there are m 'structural units as shown in the formula (III'), m 'structural units are 1 end structural units, (m' -2) intermediate structural units and another 1 end structural unit which are sequentially bonded, only one L _I"、L_II "or L _III" is bonded to L _I"、L_II "or L _III" in the intermediate structural unit adjacent thereto in each end structural unit, and 2L _I"、L_II "or L _III" is bonded to L _I"、L_II "or L _III" in the structural unit adjacent thereto, respectively, in each intermediate structural unit.

21. The antioxidant composition as set forth in claim 17, wherein the mass ratio between the ester compound and the compound represented by the formula (II') is 1:0.1 to 5.

22. The antioxidant composition as set forth in claim 1, wherein the method for producing the ester compound comprises the step of reacting the compound represented by the formula (X) with the compound represented by the formula (Y);

In the formula (X), n is an integer between 1 and 10; r ₀ is selected from the group consisting of n-valent C _1～10 linear or branched alkyl, C _2～10 linear or branched heteroalkyl; each R' group is independently selected from C _1～3 straight or branched chain alkylene; each R "group is independently selected from C _1～10 straight or branched alkyl; each R' "group is independently selected from C _1～10 straight or branched alkyl;

In formula (Y), each R _I group is independently selected from H, C _1～10 straight or branched alkyl; each x is independently selected from integers between 0 and 4; each R _II group is independently selected from H, C _1～10 straight or branched alkyl; each y is independently selected from integers between 0 and 2; each R _III group is independently selected from H, C _1～10 straight or branched alkyl; each z is independently selected from integers between 0 and 3.

23. The antioxidant composition of claim 22, wherein,

In the formula (X), n is an integer between 1 and 5; r ₀ is selected from the group consisting of n-valent C _1～20 linear or branched alkyl, C _2～20 linear or branched heteroalkyl; each R' group is independently selected from C _1～5 straight or branched chain alkylene; each R "group is independently selected from C _1～20 straight or branched alkyl; each R' "group is independently selected from C _1～20 straight or branched alkyl;

In formula (Y), each R _I group is independently selected from H, C _1～5 straight or branched alkyl; each x is independently selected from integers between 0 and 2; each R _II group is independently selected from H, C _1～5 straight or branched alkyl; each y is independently selected from 0 or 1; each R _III group is independently selected from H, C _1～5 straight or branched alkyl; each z is independently selected from integers between 0 and 2.

24. The antioxidant composition of claim 23, wherein,

In the formula (X), n is an integer between 1 and 3; r ₀ is selected from the group consisting of n-valent C _1～10 linear or branched alkyl, C _2～10 linear or branched heteroalkyl; each R' group is independently selected from C _1～3 straight or branched chain alkylene; each R "group is independently selected from C _1～10 straight or branched alkyl; each R' "group is independently selected from C _1～10 straight or branched alkyl;

In formula (Y), each R _I group is independently selected from H, C _1～3 straight or branched alkyl; each x is independently selected from 0 or 1; each R _II group is independently selected from H, C _1～3 straight or branched alkyl; each R _III group is independently selected from H, C _1～3 straight or branched alkyl; each z is independently selected from 0 or 1.

25. A process for preparing an antioxidant composition as claimed in any one of claims 1 to 24, comprising the step of mixing said ester compound, a multifunctional oiliness agent and optionally an amine compound.

26. A lubricating oil composition comprising a lubricating base oil, an antioxidant composition according to any one of claims 1 to 24.

27. Lubricating oil composition according to claim 26, characterised in that the lubricating base oil is selected from synthetic hydrocarbons and/or synthetic esters.

28. The lubricating oil composition of claim 26, wherein the lubricating base oil is selected from the group consisting of esters of the C _1～10 polyols reacted with C _3～20 fatty acids.

29. A method of improving the antioxidant and corrosion resistance of a lubricating oil composition, which comprises adding the antioxidant composition of any one of claims 1 to 24 to a lubricating base oil.