CN112779064B

CN112779064B - Low-acid diesel antiwear agent and preparation method and application thereof

Info

Publication number: CN112779064B
Application number: CN201911097019.1A
Authority: CN
Inventors: 夏鑫; 李宝石; 李妍; 蔺建民
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2019-11-11
Filing date: 2019-11-11
Publication date: 2022-12-13
Anticipated expiration: 2039-11-11
Also published as: CN112779064A

Abstract

The invention relates to a low-acid diesel antiwear agent and a preparation method thereof. The low-sulfur diesel antiwear agent is prepared by the following method: carrying out addition reaction on a raw material containing C8-C24 unsaturated fatty acid or C8-C24 unsaturated fatty acid alkyl ester and C4-C6 unsaturated dicarboxylic anhydride and/or unsaturated dicarboxylic acid to obtain alkenyl succinic anhydride and/or an alkenyl succinic acid reaction intermediate; and (b) carrying out esterification reaction on the alkenyl succinic anhydride and/or the alkenyl succinic acid and fatty alcohol according to a molar ratio of 1.6-10 to obtain alkenyl succinic diester. The antiwear agent prepared by the invention has small addition amount, can obviously improve the lubricity of low-sulfur diesel, and has small influence on the acidity of the diesel.

Description

Low-acid diesel antiwear agent and preparation method and application thereof

Technical Field

The present invention belongs to a diesel oil additive, particularly to a diesel oil antiwear agent, which is an additive for improving the lubricity of low-sulfur diesel oil.

Background

With the increasingly strict requirements of environmental protection laws, low vulcanization of diesel oil is a necessary trend. The sulfur content of diesel oil specified by national standards V and VI of diesel oil is 10 mg/kg ^-1 And below, the desulfurized diesel oil is implemented in domestic refineries, and sulfur reduction technologies such as hydrotreating and hydrocracking are adopted in China at present.

The strength of the lubricity of the diesel oil depends on the content of an anti-wear substance, the polycyclic aromatic hydrocarbon and the nitrogen-containing compound have good anti-wear effect, sulfide does not resist wear but promotes wear, but sulfide in the diesel oil mostly exists in aromatic hydrocarbon and polycyclic aromatic hydrocarbon in a heterocyclic ring form, and aromatic hydrocarbon and polycyclic aromatic hydrocarbon with lubricating property and other components with lubricating property are removed while the sulfide is greatly promoted to be removed due to serious environmental pollution. In order to avoid the abrasion and damage of the diesel engine along with the reduction of the sulfur content in the diesel, the antiwear agent is added into the low-sulfur diesel, which is the simplest and most widely adopted method for improving the lubricating property of the low-sulfur diesel at present. The method using the additive has the advantages of low cost, flexible production, little pollution and the like, and is widely regarded in industry.

The existing low-sulfur diesel oil antiwear agent mainly comprises an acid type antiwear agent and an ester type antiwear agent, wherein the acid type antiwear agent mainly comprises long-chain fatty acids such as oleic acid, linoleic acid, linolenic acid and the like, and a typical product is refined tall oil fatty acid. The ester-type antiwear agent is an esterification reaction product of the above fatty acid with a polyhydric alcohol. With the upgrading of diesel oil standards and the improvement of quality requirements, the limitation on the content of impurities and harmful substances in the acid type antiwear agent and the ester type antiwear agent is more and more strict. China petrochemical group company executes the purchasing and admittance and inspection standards of diesel anti-wear agents from 2007, and currently executes Q/SHCG 57-2017, and the purchasing standards are approved by other diesel manufacturers in China and are executed by reference in the use of anti-wear agents. The acid value of standard antiwear agents is strictly required, wherein the acid type antiwear agent requires an acid value in the range of 185-210mgKOH/g; the ester type antiwear agent requires an acid value of not more than 1mgKOH/g.

The fatty acid antiwear agents currently disclosed, such as patent US2008098642 disclose 50-95% C ₁₂ -C ₂₄ The fatty acid and the ester derivative compound prepared by taking the nutshell liquid as the raw material are used as the diesel antiwear agent. Although the antiwear effect is better, the acid value is higher. The acid additive and the high-base number dispersant have neutralization reaction to destroy the center of colloid and generate calcium salt or magnesium salt of carboxylic acid, thereby causing the problem of fuel filter screen blockage. In addition, the fatty acid type antiwear agent is used for solving the problems of diesel oil lubricity, namely the cost is relatively low, but the problems of excessive diesel oil acidity, increased corrosivity risk and the like are caused by large dosage along with the upgrading of diesel oil emission standards and the deterioration of lubricity. Patent CN108219874A discloses a formula of a compound antiwear agent for ultra-low sulfur diesel oil, tall oil fatty acid and hydroxyquinoline nitrogen-containing compounds are compounded, the compound antiwear agent can greatly reduce the addition amount of the tall oil fatty acid antiwear agent, and the compound antiwear agent is prepared by adding a solvent, a lubricant and a lubricant into a mixtureThe lubricating property of diesel oil is high, but tall oil fatty acid is easy to chemically react with metal.

At present, most of the fatty acid ester type low-sulfur diesel antiwear agents researched are fatty acid polyol esters, which have good antiwear performance and good compatibility with other diesel additives such as low-temperature flow improvers or amide ashless dispersants. There are many patents published at home and abroad relating to, for example, patent EP 0739970 which discloses a mixture of glycerides as a low sulfur diesel antiwear agent, the mixture comprising glycerides having different degrees of esterification. Patent US6511520 discloses a low sulfur diesel antiwear agent, the main components of which are fatty acid monoglyceride and fatty acid diglyceride. Patent CN 101787318A discloses a low sulfur diesel antiwear agent prepared by mixing fatty acid monoglyceride and fatty acid diglyceride and compounding with dimer acid. However, the fatty acid polyol ester is generally synthesized by partially esterifying an unsaturated fatty acid and a polyol, or by partially transesterifying an animal or vegetable fat and a polyol. In the synthesis process, a large amount of inorganic acid and alkali such as sulfuric acid and caustic soda are used as catalysts, which have strong corrosivity to equipment, a large amount of wastewater is generated in the production process, and in addition, the defects of long production period, complex preparation process and the like exist.

Disclosure of Invention

The invention provides a low-acid diesel antiwear agent based on the prior art.

The invention also provides a preparation method of the diesel antiwear agent.

The invention also provides a diesel oil composition containing the antiwear agent.

In a first aspect, the diesel antiwear agent of the present invention comprises an alkenyl succinic diester represented by structural formula 1:

wherein R is ₁ 、R ₂ Is a hydrocarbon radical with or without double bonds, R ₁ And R ₂ The total carbon number of (2) is 8 to 24, preferably 12 to 22, more preferably 16 to 20, total degree of unsaturation (total number of double bonds) of 0, 1 or 2, e.g. R ₁ And R ₂ May be alkyl, alkenyl, dienyl, and the like; r ₃ Is hydrogen or C ₁ -C ₄ Preferably hydrogen or methyl or ethyl; r is ₄ Is C ₁ -C ₄ Preferably a methylene group; r is ₅ Is C ₁ -C ₈ Is preferably C ₁ ～C ₅ Among them, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl and the like are preferable, and methyl and ethyl are preferable.

In a second aspect, the invention provides a preparation method of a low-acid diesel antiwear agent, which comprises the following steps:

(1) From a compound containing C ₈ ～C ₂₄ Unsaturated fatty acids or containing C ₈ ～C ₂₄ Starting materials for unsaturated fatty acid alkyl esters with C ₄ ～C ₆ Carrying out addition reaction on unsaturated dicarboxylic anhydride and/or unsaturated dicarboxylic acid to obtain alkenyl succinic anhydride and/or an alkenyl succinic acid reaction intermediate;

(2) And (2) carrying out esterification reaction on the alkenyl succinic anhydride and/or the alkenyl succinic acid and fatty alcohol according to a molar ratio of 1: 2.6-10 to obtain the alkenyl succinic acid diester.

In the step (1), the reaction can be carried out at a reaction temperature of 100 to 280 ℃, preferably 180 to 240 ℃. The reaction time is generally 1 to 20 hours, preferably 6 to 12 hours. The reaction may be catalyzed by an acid such as sulfuric acid, p-toluenesulfonic acid, aluminum chloride, and the like, and may be carried out without a catalyst, preferably without a catalyst.

Said compound containing C ₈ ～C ₂₄ Unsaturated fatty acids or containing C ₈ ～C ₂₄ In the unsaturated fatty acid alkyl ester raw material, the unsaturated fatty acid can be C ₈ ～C ₂₄ Long chain alkenoic acids containing one, two or three double bonds, wherein the alkyl ester may be C ₁ ～C ₄ An alkyl ester. The unsaturated fatty acid is preferably C ₁₂ ～C ₂₂ More preferably C ₁₆ ～C ₂₀ Unsaturated fatty acids, e.g. palmitoleic acid (C) ₁₆ Olefine acid) Oleic acid (C) ₁₈ Olefine acid, linoleic acid (C) ₁₈ Dienoic acid), linolenic acid (C) ₁₈ Trienoic acid), arachidonic acid (C) ₂₀ Olefine acid, erucic acid (C) ₂₂ Olefinic acid), etc., and the most preferable examples are oleic acid, linoleic acid and erucic acid, and mixtures thereof; the unsaturated fatty acid alkyl ester is preferably C ₁₂ ～C ₂₂ Unsaturated fatty acid methyl and ethyl esters, more preferably C ₁₆ ～C ₂₀ Unsaturated fatty acid methyl esters, e.g. palmitoleic acid (C) ₁₆ Olefine acid) methyl ester, oleic acid (C) ₁₈ Olefine acid) methyl ester, linoleic acid (C) ₁₈ Dienoic acid) methyl ester, linolenic acid (C) ₁₈ Trienoic acid) methyl ester, arachidonic acid (C) ₂₀ Enoate) methyl ester, erucic acid methyl ester (C) ₂₂ Olefinic acid), etc., and the most preferred examples are methyl oleate, methyl linoleate, and methyl erucate, and mixtures thereof.

Said C is ₄ ～C ₆ The unsaturated dicarboxylic anhydride being C ₄ ～C ₆ The acid anhydride of the unsaturated dicarboxylic acid may be selected from maleic anhydride, itaconic anhydride (2-methylenesuccinic anhydride), citraconic anhydride (methyl maleic anhydride), ethyl maleic anhydride, etc., and maleic anhydride is preferred.

The above unsaturated fatty acids and unsaturated fatty acid alkyl esters are simply referred to as unsaturated fatty acids (esters), the above C ₄ ～C ₆ Unsaturated dicarboxylic anhydrides and C ₄ ～C ₆ Unsaturated dicarboxylic acids are referred to simply as unsaturated acids (anhydrides).

The molar ratio of unsaturated fatty acid (ester) to unsaturated acid (anhydride) can vary from about 1. The unreacted unsaturated acid (anhydride) can be removed by vacuum distillation means such as distillation under reduced pressure and molecular distillation.

In step (2), the esterification reaction can be carried out at a temperature of 40 to 180 ℃, preferably 50 to 120 ℃. The reaction time is generally 10 minutes to 8 hours, preferably 1 hour to 5 hours. The reaction can be carried out by using an acid catalyst, such as one or more of aluminum chloride, sulfuric acid, hydrochloric acid, boron trifluoride, solid super acid, cation exchange resin, heteropoly acid and the like; it is also possible to use no catalyst, which can accelerate the reaction rate but can initiate side reactions, and it is therefore preferred not to use a catalyst.

The fatty alcohol is selected from C ₁ -C ₈ Monohydric alcohols, preferably C ₁ -C ₅ Monohydric alcohols, such as methanol, ethanol, propanol, butanol, pentanol, etc., most preferably C ₁ -C ₂ Such as methanol, ethanol. The molar ratio of alkenyl succinic anhydride or alkenyl succinic acid to fatty alcohol may be 1.

According to the process of the present invention, in the step (1) and the step (2), a reaction solvent such as toluene, xylene, ethylbenzene or the like may be further added as required.

According to the process of the present invention, in step (1) or/and step (2), an antioxidant may be added. A series of free radical chain reactions can occur in the thermal oxidation process of reactants, and chemical bonds of the reactants are broken under the action of heat, light or oxygen to generate active free radicals and hydroperoxide. The hydroperoxide undergoes decomposition reactions, which also generate hydroxyl radicals and hydroxyl radicals. These radicals can initiate a series of radical chain reactions, leading to radical changes in the structure and properties of the reactants. The antioxidant functions to scavenge the free radicals that have just been generated or to promote the decomposition of the hydroperoxide, preventing the chain reaction from proceeding. The antioxidant can be a phenolic antioxidant, such as monophenol, diphenol, bisphenol or polyphenol, or a mixture thereof in any proportion, and specifically can be: one or more of 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) isooctyl acrylate, antioxidant 1010, antioxidant 2246, antioxidant 1076, antioxidant 300 and the like; can be amine type antioxidant, such as arylamine antioxidant, for example one or more of naphthylamine derivative, diphenylamine derivative, p-phenylenediamine derivative and quinoline derivative, and specifically can be: one or more of N ', N-diphenyl-p-phenylenediamine, N' -hexamethylene-bis-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionamide, phenothiazine (vulcanized diphenylamine), antioxidant DNP, antioxidant H, antioxidant 4010 and the like; heterocyclic antioxidants, such as benzotriazole, alkyl-substituted imidazoline, 2-mercaptobenzothiazole, 2, 5-dimercapto-1, 3, 4-thiadiazole and derivatives thereof.

According to the method of the present invention, the amount of the antioxidant added may be 0.01% to 10%, preferably 0.5% to 5%, more preferably 0.5% to 1% of the total mass of the reactants.

In a third aspect, the invention provides a diesel oil composition, which comprises low-sulfur diesel oil and the diesel oil antiwear agent, wherein the sulfur content of the low-sulfur diesel oil is less than 500 mg-kg ^-1 The diesel antiwear agent provided by the invention is added into low-sulfur diesel oil in an amount of 50-500 mg/kg ^-1 Preferably 100-300 mg.kg ^-1 。

The additive provided by the invention can be used together with other additives such as a flow improver, a cetane number improver, a detergent dispersant metal deactivator, a preservative and the like according to use requirements.

The preparation method of the diesel antiwear agent provided by the invention has the advantages of easily available raw materials, low cost, simple and convenient production, small addition amount and small influence on the acidity of diesel, and can obviously improve the lubricity of low-sulfur diesel when being used as the diesel antiwear agent.

Drawings

FIG. 1 is a mass spectrum of the antiwear agent product prepared in example 2, namely: is a methyl oleate sulfosuccinate diester prepared from methyl oleate, maleic anhydride and methanol, wherein m/z =463.25 is the sodium ion mass spectrum addition peak of the methyl oleate sulfosuccinate diester prepared in example 2.

FIG. 2 is an IR spectrum of the antiwear agent product of methyl oleate-bis (methyl succinate) prepared in example 2 at 2800cm ^-1 ～3000cm ^-1 And 1450cm ^-1 Peaks indicate aliphatic hydrocarbon structure; 1737cm ^-1 The peak represents an ester group at the long chain end; 1206cm- ¹ The nearby peaks indicate the C-O structure.

Detailed Description

In examples, methyl oleate (content 96%) and ethyl oleate (content 96%) were produced by Shanghai Aradin Biotechnology Ltd, methyl erucate (content 90%) was produced by Taixi (Shanghai) chemical industry development Ltd, oleic acid (content 85%) was produced by Taixi (Shanghai) chemical industry development Ltd, anhydrous methanol (content 99.5%), anhydrous ethanol (content 99.7%) was produced by national drug group chemical reagent Ltd, maleic anhydride (content 99.5%) was produced by Beijing Yinuoka technology Ltd, and n-propanol (content 99.7%) and n-pentanol (content 98%) were produced by Shanghai Aradin Biotechnology Ltd.

The following examples further illustrate the invention.

Preparation examples 1 to 4 were used to illustrate the synthesis of alkenyl succinic anhydride, which is a reaction intermediate.

Preparation example 1

1500g of methyl oleate (96 mass percent) and 745g of maleic anhydride (the molar ratio of methyl oleate to maleic anhydride is about 1.5) are added into a 3000ml reactor equipped with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen gas introduction tube, nitrogen gas is introduced for 5-10 minutes, nitrogen protection is maintained during the reaction process, the temperature is raised to 180 ℃ by heating and stirring, reflux reaction is carried out for 5 hours, and excess maleic anhydride is removed by reduced pressure distillation, thus obtaining alkenyl succinic anhydride containing a reaction intermediate exemplified by the following structural formula 2 or structural formula 3.

Preparation example 2

In a 3000ml reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, 1500g of methyl oleate (96% by mass) and 993.4g of maleic anhydride (the molar ratio of methyl oleate to maleic anhydride is about 1: 2) were added, and about 12.5g of 2246 antioxidant (industrial grade, nanjing Ruiyi Finnish chemical plant) was added in an amount of about 0.5% of the total mass of the reactants. Introducing nitrogen for 5-10 minutes, keeping the protection of the nitrogen in the reaction process, heating and stirring to raise the temperature to 230 ℃, carrying out reflux reaction for 8 hours, and removing excessive maleic anhydride through reduced pressure distillation to obtain a reaction intermediate alkenyl succinic anhydride.

Preparation example 3

In a 1000ml reactor equipped with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen gas introduction tube, 310g of ethyl oleate (96 mass percent) and 295g of maleic anhydride (the molar ratio of ethyl oleate to maleic anhydride is about 1 3) were added, nitrogen gas was introduced for 5 to 10 minutes while maintaining the nitrogen gas protection during the reaction, the mixture was heated and stirred to 200 ℃, reflux reaction was carried out for 8 hours, and excess maleic anhydride was removed by distillation under reduced pressure to obtain the reaction intermediate alkenylsuccinic anhydride.

Preparation example 4

In a 1000ml reactor equipped with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen gas introduction tube, 500g of oleic acid (85 mass percent) and 260.4g of maleic anhydride (the molar ratio of oleic acid to maleic anhydride is about 1.5) were added, nitrogen gas was introduced for 5 to 10 minutes while maintaining the nitrogen gas protection during the reaction, the mixture was heated and stirred to 170 ℃, reflux reaction was carried out for 6 hours, and excess maleic anhydride was removed by distillation under reduced pressure to obtain alkenyl succinic anhydride as a reaction intermediate.

Examples 1-8 are provided to illustrate the synthesis of alkenyl succinic acid diester represented by structural formula 1. In the examples, the acid value of the antiwear product is determined by the method GB/T7304-2014 potentiometric titration method for the acid value of petroleum products.

Example 1:

cooling the product of preparation example 1 to 60 ℃, taking 500g of the product, placing the 500g of the product into a 1000ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, adding 103.8g of methanol (the molar ratio of alkenyl succinic anhydride to fatty alcohol is 1. The acid value was 1.09mgKOH/g.

Example 2:

cooling the product of preparation example 2 to 70 ℃, placing 500g into a 1000ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, adding 218g of methanol (the molar ratio of alkenyl succinic anhydride to fatty alcohol is 1: 5), introducing nitrogen for 5-10 minutes, stirring at constant temperature of 70 ℃, reacting for 4 hours, and cooling to obtain the dimethylesteroleate-based succinic acid dimethylol ester product containing the example of the following structural formula 4 or structural formula 5. The acid value was 0.82mgKOH/g.

Example 3:

cooling the product of preparation example 3 to 100 ℃, putting 150g of the product into a 500ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, adding 183g of n-propanol (the molar ratio of alkenyl succinic anhydride to fatty alcohol is 1. The acid value was 0.71mgKOH/g.

Example 4:

cooling the product of preparation example 2 to 90 ℃, taking 500g of the product, placing the 500g of the product in a 1000ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, adding 364g of methanol (the molar ratio of alkenyl succinic anhydride to fatty alcohol is 1. The acid value was 0.88mgKOH/g.

Example 5:

cooling the product of preparation example 3 to 80 ℃, taking 150g, placing the 150g into a 250ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, adding 52.8g of ethanol (the molar ratio of alkenyl succinic anhydride to fatty alcohol is 1. The acid value was 0.92mgKOH/g.

Example 6:

cooling the product of preparation example 2 to 70 ℃, taking 500g of the product, placing the 500g of the product in a 1000ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, adding 559g of n-amyl alcohol (the molar ratio of alkenyl succinic anhydride to fatty alcohol is 1. The acid value was 0.83mgKOH/g.

Example 7:

120g of methyl erucate (the mass fraction is 90%, produced by TCI company, japan) and 60.2g of maleic anhydride (the molar ratio of methyl erucate to maleic anhydride is about 1, 2) are placed in a 250ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen gas introduction tube, nitrogen gas is introduced for 5-10 minutes, the mixture is heated and stirred to 225 ℃, the reaction is carried out for 10 hours, and excess maleic anhydride is removed through reduced pressure distillation, thus obtaining the methyl erucate succinic anhydride reaction intermediate.

After the erucic acid methyl ester succinic anhydride reaction intermediate is cooled to 70 ℃, 100g of the erucic acid methyl ester succinic anhydride reaction intermediate is placed into a 250ml reactor which is provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, 38.8g of methanol (the molar ratio of alkenyl succinic anhydride to methanol is 1.

Example 8:

cooling the product of preparation example 4 to 70 ℃, taking 500g of the product, placing the 500g of the product in a 1000ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, adding 110g of methanol (the molar ratio of alkenyl succinic anhydride to fatty alcohol is 1. The acid value was 1.13mgKOH/g.

Comparative example 1:

methyl oleate (96% by mass, shanghai Allantin Biotechnology Co., ltd.).

Comparative example 2:

oleic acid (85% by weight, produced by Chishiai (Shanghai) chemical industry development Co., ltd.) was added at 200 mg/kg ^-1 Adding into base diesel oil, and carrying out diesel oil abrasion test.

Comparative example 3:

afton 4140 (commercial diesel antiwear agent, afton, USA).

Example 9 lubricity test

Lubricity of Diesel oil the scuffing Diameter (Wear Scar Diameter, WSD) at 60 ℃ was measured on a High-Frequency Reciprocating tester (HFRR) (manufactured by PCS instruments of the United kingdom) according to the method described in CEC-F-06-A-96 or ISO/FDIS 12156-1 (ASTM D6079), and the reported result WS1.4 was obtained by correcting the influence of temperature and humidity. The HFRR method (ISO 12156-1) trace diameter WS1.4 of the diesel before and after addition is shown in Table 2, wherein the smaller the trace diameter, the better the lubricity of the diesel. At present, most of diesel oil standards in the world, such as European standard EN 590 and China automotive diesel oil standard GB/T19147, use the trace grinding diameter less than 460 μm (60 ℃) as the basis of the qualified diesel oil lubricity standard.

The sulfur content of the low-sulfur diesel oil used in the lubricating property test is 6mg kg ^-1 、11mg·kg ^-1 Specific properties of diesel fuels having respective worn-spot diameters of 640 μm and 545 μm are shown in Table 1.

TABLE 1 physicochemical Properties of Diesel oil

The antiwear agent prepared by the method is added into low-sulfur diesel oil for lubricating performance test, and the test result is shown in table 2.

TABLE 2 improvement of lubricity of diesel fuel by antiwear product

As can be seen from the table 2, the lubricating property of low-sulfur diesel oil can be greatly improved by adding a small amount of the product provided by the invention, so that the lubricating property of the low-sulfur diesel oil can be well improved by the diesel oil antiwear agent provided by the invention. Particularly, the unexpected effect of the alkenyl succinic acid double methanol ester and the alkenyl succinic acid double ethanol ester product on improving the lubricating property of the diesel oil is most obvious and is far better than that of the alkenyl succinic acid double propylene ester or the alkenyl succinic acid double amyl alcohol ester.

Example 9 acidity test

The acidity of the diesel oil sample added with the diesel oil antiwear agent is tested according to the method specified in GB/T258-2016 acidity test for light petroleum products, and the results are shown in Table 3.

TABLE 3 Effect of antiwear product on Diesel acidity

As can be seen from Table 3, the antiwear product prepared had little effect on the acidity of the diesel.

The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention will still fall within the protection scope of the technical solution of the present invention.

Claims

1. A diesel antiwear agent comprising an alkenyl succinic diester represented by the following structural formula 1:

wherein R is ₁ 、R ₂ Is a hydrocarbon radical with or without double bonds, R ₁ And R ₂ The total carbon number of (2) is 8-24, the total double bond number is 0, 1 or 2 ₃ Is hydrogen or C ₁ -C ₄ A hydrocarbon group of R ₄ Is C ₁ -C ₃ A hydrocarbon group of R ₅ Is C ₁ -C ₂ Alkyl group of (1).

2. The antiwear agent of claim 1, wherein R ₁ 、R ₂ Total carbon number of 12 to 22 ₃ Is hydrogen or methyl or ethyl; r ₄ Is a methylene group; r is ₅ Is methyl or ethyl.

3. The antiwear agent of claim 1, wherein R ₁ 、R ₂ Total carbon number of 16-20.

4. A method of making the diesel antiwear agent of any one of claims 1 to 3, comprising the steps of:

(1) From a compound containing C ₈ ～C ₂₄ Unsaturated fatty acids or containing C ₈ ～C ₂₄ Starting materials for unsaturated fatty acid alkyl esters and C ₄ ～C ₆ Carrying out addition reaction on unsaturated dicarboxylic anhydride and/or unsaturated dicarboxylic acid to obtain alkenyl succinic anhydride and/or alkenyl succinic acid reaction intermediate;

(2) The alkenyl succinic anhydride and/or alkenyl succinic acid and C ₁ -C ₂ The fatty alcohol is subjected to esterification reaction according to a molar ratio of 1.

5. The method according to claim 4, wherein, in the step (1), the reaction temperature is 100 to 280 ℃.

6. The method according to claim 4, wherein the reaction temperature in the step (1) is 180 to 240 ℃.

7. The method according to claim 4, wherein the C is contained ₈ ～C ₂₄ Unsaturated fatty acids or containing C ₈ ～C ₂₄ In the unsaturated fatty acid alkyl ester raw material, the unsaturated fatty acid is C ₈ ～C ₂₄ Long chain alkenoic acids containing one, two or three double bonds, wherein the alkyl ester is C ₁ ～C ₄ An alkyl ester.

8. The method according to claim 4, wherein the unsaturated fatty acid is selected from C ₁₂ ～C ₂₂ Unsaturated fatty acids; and/or the unsaturated fatty acid alkyl ester is selected from C ₁₂ ～C ₂₂ Unsaturated fatty acid methyl esters and ethyl esters.

9. The method according to claim 4, wherein the unsaturated fatty acid is selected from C ₁₆ ～C ₂₀ Unsaturated fatty acids; and/or the unsaturated fatty acid alkyl ester is selected from C ₁₆ ～C ₂₀ Unsaturated fatty acid methyl ester.

10. The method of claim 4, wherein the unsaturated fatty acid is selected from the group consisting of oleic acid, linoleic acid, and erucic acid, and mixtures thereof; and/or the unsaturated fatty acid alkyl ester is selected from methyl oleate, methyl linoleate and methyl erucate and a mixture thereof.

11. The method according to claim 4, wherein said C ₄ ～C ₆ The unsaturated dicarboxylic anhydride is selected from maleic anhydride, itaconic anhydride, citraconic anhydride, and ethylmaleic anhydride.

12. The process according to claim 4, wherein in the step (1), the molar ratio of the unsaturated fatty acid or unsaturated fatty acid alkyl ester to the unsaturated dicarboxylic anhydride and/or unsaturated dicarboxylic acid is between 1.

13. The production process according to claim 4, wherein in the step (1), the molar ratio of the unsaturated fatty acid or unsaturated fatty acid alkyl ester to the unsaturated dicarboxylic anhydride and/or unsaturated dicarboxylic acid is 1.

14. The production method according to claim 4, wherein, in the step (2), the esterification reaction temperature is 40 to 180 ℃.

15. The production method according to claim 4, wherein, in the step (2), the esterification reaction temperature is 50 to 120 ℃.

16. The preparation method according to claim 4, wherein an antioxidant is further added in the step (1) or/and the step (2).

17. The production method according to claim 4, wherein the molar ratio of the alkenylsuccinic anhydride and/or alkenylsuccinic acid to the fatty alcohol is 1.

18. A diesel oil composition comprising a low sulfur diesel oil and the diesel oil anti-wear agent according to any one of claims 1 to 3, wherein the diesel oil anti-wear agent is added to the low sulfur diesel oil in an amount of 50 to 500 mg/kg ^-1 。

19. The diesel composition of claim 18 wherein the diesel antiwear agent is added in an amount of 100 to 300 mg-kg in low sulfur diesel ^-1 。