阅读说明：本技术 一种低硫柴油抗磨剂及其制备方法和应用 (Low-sulfur diesel antiwear agent and preparation method and application thereof ) 是由 夏鑫 李妍 李宝石 蔺建民 于 2019-11-11 设计创作，主要内容包括：本发明涉及一种低硫柴油抗磨剂及其制备方法,所述柴油抗磨剂含有烯基琥珀酸单酯和烯基琥珀酸双酯,其制备方法可以是将不饱和脂肪酸(酯)与不饱和酸酐或不饱和二羧酸经加成反应获得不饱和脂肪酸(酯)基琥珀酸(酐)中间体,再与脂肪醇进行酯化反应而获得抗磨剂产品。所制备的抗磨剂在基础柴油中的添加量小,且能够显著提高低硫柴油的润滑性。(The invention relates to a low-sulfur diesel antiwear agent and a preparation method thereof, wherein the diesel antiwear agent contains alkenyl succinic acid monoester and alkenyl succinic acid diester, and the preparation method comprises the steps of carrying out addition reaction on unsaturated fatty acid (ester) and unsaturated anhydride or unsaturated dicarboxylic acid to obtain an unsaturated fatty acid (ester) base succinic acid (anhydride) intermediate, and carrying out esterification reaction on the unsaturated fatty acid (ester) base succinic acid (anhydride) intermediate and fatty alcohol to obtain an antiwear agent product. The addition amount of the prepared antiwear agent in the base diesel oil is small, and the lubricity of the low-sulfur diesel oil can be remarkably improved.)

1. A diesel antiwear agent comprising an alkenyl succinic acid diester represented by the following structural formula 1 and an alkenyl succinic acid monoester represented by the following structural formula 2:

wherein R is₁、R₂Is a hydrocarbon radical with or without double bonds, R₁And R₂The total carbon number of (2) is 8-24, the total double bond number is 0, 1 or 2, R₃Is hydrogen or C₁-C₄A hydrocarbon group of R₄Is C₁-C₃A hydrocarbon group of R₅Is C₁-C₈A hydrocarbon group of (1).

2. The antiwear agent of claim 1, wherein R₁、R₂12 to 22, more preferably 16 to 20, R₃Is hydrogen or methyl or ethyl; r₄Is methylene; r₅Is C₁～C₅Alkyl group of (1).

3. The antiwear agent according to claim 1, wherein the molar ratio of alkenyl succinic acid diester to alkenyl succinic acid monoester is 1:1 to 10.

4. A preparation method of a diesel antiwear agent comprises the following steps:

(1) from a composition containing C₈～C₂₄Unsaturated fatty acids or containing C₈～C₂₄Starting materials for unsaturated fatty acid alkyl esters and C₄～C₆Carrying 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) and carrying out esterification reaction on the alkenyl succinic anhydride and/or the alkenyl succinic acid and fatty alcohol according to the molar ratio of 1: 1.3-2.5 to obtain alkenyl succinic acid monoester and alkenyl succinic acid diester.

5. The preparation method according to claim 4, wherein, in the step (1), the reaction temperature is 100-280 ℃, preferably 180-240 ℃.

6. The method according to claim 4, wherein the C-containing compound is₈～C₂₄Unsaturated fatty acids or containing C₈～C₂₄In the unsaturated fatty acid alkyl ester raw material, the unsaturated fatty acid is C₈～C₂₄Long chain alkenoic acids containing one, two or three double bonds, wherein the alkyl ester is C₁～C₄An alkyl ester.

7. The method according to claim 4, wherein the C-containing compound is₈～C₂₄Unsaturated fatty acids, preferably C₁₂～C₂₂Unsaturated fatty acids, more preferably oleic acid, linoleic acid and erucic acid, and mixtures thereof; and/or, said compound contains C₈～C₂₄The unsaturated fatty acid alkyl ester is selected from methyl oleate, methyl linoleate and methyl erucate and mixtures thereof or biodiesel, preferably biodiesel with an unsaturated fatty acid methyl ester content of greater than 80%, more preferably greater than 90%.

8. The method according to claim 4, wherein said C is₄～C₆The unsaturated dicarboxylic anhydride is selected from maleic anhydride, itaconic anhydride, citraconic anhydride, ethylmaleic anhydride, said C₄～C₆Unsaturated dicarboxylic acids are defined by the above-mentioned C₄～C₆Formed by hydrolysis of unsaturated anhydridesA dicarboxylic acid.

9. 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 1:0.5 to 3, preferably 1:1 to 2.

10. The production process according to claim 4, wherein, in the step (2), the esterification reaction temperature is 40 to 180 ℃, preferably 50 to 120 ℃.

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

12. The method according to claim 4, wherein the fatty alcohol is selected from C₁-C₈Monohydric alcohols, preferably C₁-C₅Monohydric alcohol, more preferably C₁-C₂A monohydric alcohol of (1).

13. The production method according to claim 4, wherein the molar ratio of the alkenylsuccinic anhydride and/or alkenylsuccinic acid to the fatty alcohol is 1:1.5 to 2.0.

14. A diesel antiwear agent prepared by the method of any one of claims 3 to 13.

15. A diesel oil composition comprising a low sulfur diesel oil and the diesel oil anti-wear agent of any one of claims 1 to 3 or 13, wherein the diesel oil anti-wear agent is added to the low sulfur diesel oil in an amount of 50 to 500 mg-kg^-1Preferably 100-300 mg-kg^-1。

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^-1And below, desulfurized diesel oil is implemented in domestic refineries and currently collected in domesticThe sulfur reduction technology such as hydrotreating and hydrocracking is adopted.

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 in 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, low pollution and the like, and is widely regarded in industry. The low-sulfur diesel antiwear agent is mostly a derivative of fatty acid, fatty acid alkyl ester, amine or amide.

At present, there are many patents disclosing the research of vegetable oils as anti-wear agents for low sulfur diesel oil directly. Patent EP 0605857 discloses the use of natural oils and fats such as rapeseed oil, sunflower oil, castor oil, etc. directly as low sulfur diesel antiwear agents. Although the vegetable oil has the advantages of easily available raw materials, low price and the like, the use effect is relatively poor, and the industrial application is difficult. Research results show that the lubricity can be greatly improved by adding the biodiesel into the low-sulfur diesel, and the additional value of the biodiesel can be remarkably improved. However, the lubricating effect of biodiesel can only be achieved at a higher addition amount, and the addition amount is usually more than 0.8% (volume fraction) so as to reduce the wear scar diameter of low-sulfur diesel to less than 460 μm (Yanghua, etc., the enhancing effect of biodiesel on the lubricity of low-sulfur diesel [ J ], petroleum refining and chemical industry, 2005,36(7):25-28), so that the economy of biodiesel as a diesel antiwear agent is poor. Therefore, it is necessary to improve the lubricity of biodiesel by molecular modification means and to reduce the amount of biodiesel added to low-sulfur diesel.

Patent CN1990835A discloses a preparation method of modified biodiesel capable of being used as an antiwear agent of low-sulfur diesel, the required addition amount is far less than that of biodiesel directly used as an antiwear agent, and the disclosed technical means is that biodiesel and polyalcohol perform ester exchange reaction or biodiesel and organic amine perform aminolysis reaction, so that the modified biodiesel is obtained. However, the aminolysis reaction with organic amine as the raw material also introduces N atoms into the product, which is not in line with the development trend of low-sulfur diesel oil cleanness and is difficult to develop in large scale in the future. CN108003950A discloses a composition with diesel anti-wear performance, a diesel composition and a preparation method thereof. The composition contains unsaturated fatty glyceride, and the preparation method of the composition comprises rectifying the biodiesel, including the biodiesel by urea and/or freezing at low temperature, and then contacting the biodiesel with glycerol to perform transesterification reaction. Patent US5891203 discloses biodiesel and fatty acid diethanolamine derivatives as diesel antiwear agents in combination, but also has problems of compatibility and high production cost of the antiwear agents.

CN106929112A discloses a method for improving the abrasion resistance of low-sulfur diesel, which improves the lubricity of diesel by esterification reaction products of alkenyl succinic anhydride and monohydric aliphatic alcohol, but the product has high viscosity and general effect of improving the lubricity of ultra-low-sulfur diesel (such as vehicle diesel reaching the national VI emission standard), and meanwhile, the alkenyl in the alkenyl succinic anhydride is derived from oligomerization of ethylene, propylene or butylene, and the active ingredients in the product are low and do not belong to renewable resources.

Disclosure of Invention

The invention provides a low-sulfur diesel antiwear agent based on the prior art, and the antiwear agent has excellent lubricating property and anti-corrosion property.

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 contains alkenyl succinic acid diester shown in a structural formula 1 and alkenyl succinic acid monoester shown in a structural formula 2.

The alkenyl succinic acid diester and the alkenyl succinic acid monoester can be in any proportion, and the preferable molar ratio of the alkenyl succinic acid diester to the alkenyl succinic acid monoester is 1: 1-10.

Wherein R is₁、R₂Is a hydrocarbon radical with or without double bonds, R₁And R₂Has a total carbon number of 8 to 24, preferably 12 to 22, more preferably 16 to 20, and a total degree of unsaturation (total number of double bonds) of 0, 1 or 2, for example R₁And R₂May be alkyl, alkenyl, dienyl, and the like; r₃Is hydrogen or C₁-C₄Preferably hydrogen or methyl or ethyl; r₄Is C₁-C₄Preferably a methylene group; r₅Is C₁-C₈Is preferably C₁～C₅Among them, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl and the like are preferable, and C is most preferable₁-C₂Such as methyl, ethyl.

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

(1) from a composition containing C₈～C₂₄Unsaturated fatty acids or containing C₈～C₂₄Starting materials for unsaturated fatty acid alkyl esters and C₄～C₆Carrying 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) and carrying out esterification reaction on the alkenyl succinic anhydride and/or the alkenyl succinic acid and fatty alcohol to obtain alkenyl succinic acid diester and alkenyl succinic acid monoester.

In step (1), the reaction can be carried out at the reaction temperature of 100 ℃ and 280 ℃, preferably at the reaction temperature of 180 ℃ and 240 ℃. The reaction time is generally 1 to 20 hours, preferably 6 to 12 hours. The reaction may be catalyzed by acids 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 C₈～C₂₄Unsaturated fatty acids or containing C₈～C₂₄Raw material of unsaturated fatty acid alkyl esterWherein the unsaturated fatty acid may be C₈～C₂₄Long chain alkenoic acids containing one, two or three double bonds, wherein the alkyl ester may be C₁～C₄An alkyl ester. The unsaturated fatty acid is preferably C₁₂～C₂₂More preferably C₁₆～C₂₀Unsaturated fatty acids, e.g. palmitoleic acid (C)₁₆Olefine acid, oleic acid (C)₁₈Olefine acid, linoleic acid (C)₁₈Dienoic acid), linolenic acid (C)₁₈Trienoic acid), arachidonic acid (C)₂₀Olefine acid, erucic acid (C)₂₂Olefinic 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 C₁₂～C₂₂Unsaturated fatty acid methyl and ethyl esters, more preferably C₁₆～C₂₀Unsaturated fatty acid methyl esters, e.g. palmitoleic acid (C)₁₆Olefine acid) methyl ester, oleic acid (C)₁₈Olefine acid) methyl ester, linoleic acid (C)₁₈Dienoic acid) methyl ester, linolenic acid (C)₁₈Trienoic acid) methyl ester, arachidic acid (C)₂₀Olefine acid) methyl ester, erucic acid methyl ester (C)₂₂Olefinic acid), etc., and the most preferred examples are methyl oleate, methyl linoleate, and methyl erucate, and mixtures thereof.

Said compound containing C₈～C₂₄The unsaturated fatty acid alkyl ester is preferably biodiesel, and the chemical composition of biodiesel is fatty acid monoalkyl ester, mainly C₈～C₂₄Fatty acid methyl ester, wherein the unsaturated fatty acid methyl ester is contained, the present invention preferably selects biodiesel with high unsaturated fatty acid methyl ester content, such as biodiesel with unsaturated fatty acid methyl ester content of more than 60%, preferably more than 80%, and further preferably biodiesel with unsaturated fatty acid methyl ester content of more than 90%, more preferably more than 96%. The biodiesel with high content of unsaturated fatty acid methyl ester can be biodiesel produced by using oil raw materials with high content of unsaturated fatty acid, and can also be biodiesel with high content of unsaturated fatty acid methyl ester obtained by removing saturated fatty acid methyl ester in the biodiesel through reduced pressure distillation (rectification) and/or low-temperature freezing crystallization.

The biodiesel refers to natural oil and fatLower alcohols (e.g. C)₁～C₅Fatty alcohol) is generated through ester exchange (alcoholysis) reaction, and the generated fatty acid low-carbon alcohol ester is generally fatty acid monoester, namely the ester exchange product of modified natural oil and methanol. The natural oil can be vegetable oil or animal oil. Such as peanut oil, corn oil, cottonseed oil, rapeseed oil, soybean oil, palm oil, safflower oil, linseed oil, coconut oil, sesame oil, olive oil, sunflower oil, tall oil, lard, tallow, fish oil, etc., either fresh oil or recycled waste oil. There are many known biodiesel production processes, and most commonly, a catalyst is used to catalyze the transesterification reaction, i.e., the natural oil and fat and lower alcohol are alcoholyzed into fatty acid lower alcohol ester and glycerol under the action of the catalyst. The catalysts generally used are mainly acids such as sulfuric acid, p-toluenesulfonic acid and the like, and bases such as sodium hydroxide, potassium hydroxide, sodium methoxide, sodium carbonate, methylcyclohexane, triethylamine, piperidine and the like; lipases can also be used as catalysts. Besides the catalyst, the biodiesel can be produced by ester exchange under the condition of inorganic catalyst such as critical method and supercritical method. This requires high temperatures and pressures and a large excess of methanol, with the advantage of a simple, safe and efficient transesterification process.

Said C is₄～C₆The unsaturated dicarboxylic anhydride is selected from maleic anhydride, itaconic anhydride (2-methylenesuccinic anhydride), citraconic anhydride (methyl maleic anhydride), ethyl maleic anhydride, etc., preferably maleic anhydride. Said C is₄～C₆Unsaturated dicarboxylic acids are defined by the above-mentioned C₄～C₆The unsaturated anhydride is hydrolyzed to form the dicarboxylic acid.

The above unsaturated fatty acids and unsaturated fatty acid alkyl esters are referred to simply as unsaturated fatty acids (esters), above C₄～C₆Unsaturated dicarboxylic anhydrides and C₄～C₆Unsaturated dicarboxylic acids are referred to simply as unsaturated acids (anhydrides).

The molar ratio of unsaturated fatty acid (ester) to unsaturated acid (anhydride) may vary from about 1:0.5 to 3, e.g., 1:1.3, and maleic anhydride may be used in excess to drive the reaction to completion. Unreacted maleic anhydride can be removed by vacuum distillation means such as vacuum distillation 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 30 minutes 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, and preferably not, to use a catalyst.

The fatty alcohol is selected from C₁-C₈Monohydric alcohols, preferably C₁-C₅Monohydric alcohols, most preferably C₁-C₂Monohydric alcohols, such as methanol, ethanol. The molar ratio of the alkenyl succinic anhydride or the alkenyl succinic acid to the fatty alcohol may be 1:1.3 to 2.5, preferably 1:1.5 to 2.0.

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 of the invention, wherein the sulfur content of the low-sulfur diesel oil is less than 500mg kg < -1 >, and the diesel oil antiwear agent provided by the invention is added into the low-sulfur diesel oil in an amount of 50-500mg kg < -1 >, preferably 100 mg kg < -1 >.

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

The preparation method of the diesel antiwear agent provided by the invention has the advantages of easily available raw materials, renewable resources, low cost, simple and convenient production and small addition amount, 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 product prepared in example 1, namely: the anti-wear agent is prepared by using biodiesel with the methyl oleate content of 65.64% (mass fraction), maleic anhydride and methanol as raw materials, wherein m/z is 449.29 which is a mass spectrum addition peak of combined sodium ions of the anti-wear agent product prepared in the example 1, namely the product corresponds to the product of monoesterification of methyl oleate alkenyl succinic anhydride; the antiwear agent prepared in example 1 has a peak associated with proton addition of sodium ions at 463.30, which corresponds to the product of the bis-esterification of methyl oleate alkenyl succinic anhydride. The ratio of mono-and di-esterified esters was about 2.5: 1.

FIG. 2 is an IR spectrum of the antiwear product of example 1, 2800cm^-1～3000cm^-1And 1450cm^-1Peaks indicate fatty hydrocarbon knotsStructuring; 1735cm^-1The peak represents the ester group at the long chain end; 1217cm-¹Nearby peaks indicate C-O structure; 3000cm^-1Near and 1640cm^-1The peaks near represent carbon-carbon double bonds.

Detailed Description

In these examples, the lubricity of the diesel fuel was measured on a High-Frequency Reciprocating Rig (HFRR) (manufactured by PCS instruments of the UK.) in accordance with the method described in CEC-F-06-A-96 or ISO/FDIS12156-1 (ASTM D-6079), and the trace Diameter at 60 ℃ (Wear Scar Diameter, WSD) was measured and the reported result WS1.4 was obtained by correcting the influence of temperature and humidity.

The invention uses the biodiesel as a raw material, so that the biodiesel obtained by any mode can be used in the invention. In the present invention, since biodiesel is generally mixed fatty acid methyl ester mainly containing octadecanoic acid, the molecular weight thereof can be regarded as the same as that of methyl oleate (molecular weight 296) for the purpose of calculating the charge ratio.

In the preparation examples, maleic anhydride (content: 99.5%) was produced by Technology Ltd of YinoKay, Beijing. Preparation examples 1 to 4 are provided to illustrate the synthesis of alkenyl succinic anhydride, which is a reaction intermediate.

Preparation example 1

600g of biodiesel (the manufacturer is Fujian Longyan distinguished New energy Co., Ltd., fatty acid ester is composed of methyl stearate 1.6%, methyl oleate 65.64%, methyl linoleate 18.16%, methyl linolenate 8.1%) and 298g of maleic anhydride (the molar ratio of methyl oleate to maleic anhydride is about 1:1.5) are added into a 1000ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen gas inlet tube, nitrogen gas is introduced into the reactor for 5-10 minutes, the temperature is raised to 220 ℃ under the protection of nitrogen gas during the reaction process, reflux reaction is carried out for 5 hours, and excessive maleic anhydride is removed through reduced pressure distillation, so that the reaction intermediate alkenyl succinic anhydride containing the examples of the following structural formula 3 or/and structural formula 4 is obtained.

Preparation example 2

1500g of methyl oleate (96% by weight, Shanghai Aladdin Biochemical technology Co., Ltd.) and 993.4g of maleic anhydride (the molar ratio of methyl oleate to maleic anhydride is about 1:2) were added to a 3000ml reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, and about 12.5g of 2246 antioxidant (technical grade, Nanjing Ruiyi Kaisha) was added in an amount of about 0.5% by weight based on the total mass of the reactants. And 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

Palm oil biodiesel was processed according to the method disclosed in example 2 of CN108003950A to obtain biodiesel with unsaturated fatty acid methyl ester content over 90%, and then reacted with maleic anhydride. The treatment comprises two processes of rectification and cryogenic freezing filtration, and the compositions of the biodiesel before and after the treatment are measured according to the method EN 14103 and are shown in Table 1.

TABLE 1

Adding 1500g of biodiesel obtained by processing palm oil biodiesel and 1100g of maleic anhydride (the molar ratio of unsaturated fatty acid methyl ester to maleic anhydride is about 1:2.5) into a 3000ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, introducing nitrogen for 5-10 minutes, keeping nitrogen protection in the reaction process, and adding 13g of 2246 antioxidant (industrial grade, Nanjing Rui Yanhua factory), wherein the addition amount of the antioxidant is about 0.5% of the total mass of reactants. Heating and stirring the mixture to raise the temperature to 200 ℃, carrying out reflux reaction for 9 hours, and removing excessive maleic anhydride through reduced pressure distillation to obtain a reaction intermediate alkenyl succinic anhydride.

Preparation example 4

Adding 500g of oleic acid (85 mass percent, Chiese chemical industry development limited) and 260.4g of maleic anhydride (the molar ratio of the oleic acid to the maleic anhydride is about 1:1.5) into a 1000ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, introducing nitrogen for 5-10 minutes, keeping nitrogen protection in the reaction process, heating and stirring to 170 ℃, carrying out reflux reaction for 6 hours, and removing excessive maleic anhydride through reduced pressure distillation to obtain a reaction intermediate alkenyl succinic anhydride.

Examples

In the examples, anhydrous methanol (content: 99.5%), anhydrous ethanol (content: 99.7%) were produced by the national pharmaceutical group chemical reagent company, and n-propanol (content: 99.7%) and n-pentanol (content: 98%) were produced by the Shanghai Aladdin Biotechnology Ltd.

Examples 1-10 are provided to illustrate the synthesis of alkenyl succinates of formula 1 and formula 2.

Example 1:

putting 100g of the product of the preparation example 1 into a 250ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, adding 11.0g of methanol (the molar ratio of the alkenyl succinic anhydride reaction intermediate to the methanol is about 1:1.3), introducing nitrogen for 5-10 minutes, stirring at constant temperature of 70 ℃, reacting for 2 hours, and cooling to room temperature to obtain the alkenyl succinate antiwear agent products of the structural formula 4 and the structural formula 5 or/and the structural formula 6 and the structural formula 7.

Example 2:

putting 150g of the product 1 of the preparation example 2 into a 250ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, adding 21.9g of methanol (the molar ratio of the alkenyl succinic anhydride reaction intermediate to the methanol is about 1:1.8) and 1.7g of aluminum chloride, introducing nitrogen for 5-10 minutes, stirring at constant temperature of 60 ℃, reacting for 0.5 hour, cooling to room temperature, standing for 24 hours, and removing the aluminum chloride to obtain the product.

Example 3:

putting 50g of the product prepared in the preparation example 3 into a 100ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, adding 14.9g of ethanol (the molar ratio of the alkenyl succinic anhydride reaction intermediate to the ethanol is about 1:2.5), introducing nitrogen for 5-10 minutes, stirring at the constant temperature of 80 ℃, reacting for 1 hour, and cooling to the room temperature to obtain the antiwear agent product.

Example 4:

50g of the reaction product obtained in the preparation example 3 is placed in a 100ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, 8.2g of methanol (the molar ratio of the alkenyl succinic anhydride reaction intermediate to the methanol is about 1:2) is added, nitrogen is introduced for 5-10 minutes, the mixture is stirred at a constant temperature of 90 ℃ for 2 hours, and the mixture is cooled to room temperature, so that the antiwear agent product is obtained.

Example 5:

after cooling the reaction product of preparation example 4 to 100 ℃, 50g of the reaction product is placed into a 100ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, 6.1g of methanol (the molar ratio of the alkenyl succinic anhydride reaction intermediate to the methanol is about 1:1.5) is added, nitrogen is introduced for 5-10 minutes, the reaction is carried out at a constant temperature of 80 ℃ for 5 hours, and the reaction product is cooled to room temperature, thus obtaining the antiwear agent product.

Example 6:

after cooling the reaction product of preparation example 4 to 100 ℃, 50g of the reaction product is placed into a 100ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, 7.2g of methanol (the molar ratio of the alkenyl succinic anhydride reaction intermediate to the methanol is about 1:1.8) is added, nitrogen is introduced for 5-10 minutes, the reaction product is stirred at constant temperature of 80 ℃ for 5 hours, and the anti-wear agent product is obtained after cooling to room temperature.

Example 7:

after cooling the reaction product of preparation example 3 to 110 ℃, 50g of the reaction product is placed into a 100ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, 9.8g of ethanol (the molar ratio of the alkenyl succinic anhydride reaction intermediate to the ethanol is about 1:1.7) is added, nitrogen is introduced for 5-10 minutes, the reaction product is stirred at a constant temperature of 110 ℃ for 3 hours, and the anti-wear agent product is obtained after cooling to room temperature.

Example 8:

after cooling the reaction product of preparation example 2 to 100 ℃, 50g of the reaction product is placed into a 100ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen gas introduction tube, 12g of n-propanol (the molar ratio of the alkenyl succinic anhydride reaction intermediate to the n-propanol is about 1:1.5) is added, nitrogen gas is introduced for 5-10 minutes, the reaction product is stirred at constant temperature of 100 ℃ and is reacted for 8 hours, and the anti-wear agent product is obtained after cooling to room temperature.

Example 9:

after cooling the reaction product of preparation example 1 to 70 ℃, 50g of the reaction product is placed in a 100ml reactor provided with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen inlet tube, 14.8g of n-amyl alcohol (the molar ratio of the alkenyl succinic anhydride reaction intermediate to the n-amyl alcohol is about 1:1.3) is added, nitrogen is introduced for 5-10 minutes, the reaction product is stirred at constant temperature of 140 ℃ for 1 hour, and the reaction product is cooled to room temperature to obtain the antiwear agent product.

Example 10:

after cooling the reaction product of preparation example 4 to 70 ℃, 150g of the reaction product was placed in a 250ml reactor equipped with an electric stirrer, a thermometer, a reflux cold energy tube and a nitrogen gas introduction tube, 33g of methanol (the molar ratio of the alkenyl succinic anhydride reaction intermediate to methanol was about 1:2.5) was added, nitrogen gas was introduced for 5 to 10 minutes, the reaction was stirred at a constant temperature of 80 ℃ for 1 hour, and the antiwear agent product was obtained after cooling to room temperature.

Comparative example 1:

biodiesel (produced by Fujian Longyan excellence new energy Co., Ltd., fatty acid ester comprises methyl stearate 1.6%, methyl oleate 65.64%, methyl linoleate 18.16%, and methyl linolenate 8.1%).

Comparative example 2:

oleic acid (85% by mass, tai xi ai (shanghai) chemical industry development limited).

Comparative example 3:

according to the patent CN106929112A, the method for improving the wear resistance of low-sulfur diesel oil comprises the steps of self-preparing octadecenyl succinic anhydride, heating maleic anhydride, 1-octadecene and a small amount of p-hydroxyanisole under the stirring condition to reflux under the protection of nitrogen, reacting at constant temperature, cooling to room temperature under the protection of nitrogen after the reaction is finished, and recovering unreacted raw materials and octadecenyl succinic anhydride products through reduced pressure distillation. 50g of octadecenyl succinic anhydride and 10g of absolute ethyl alcohol are placed in a three-neck flask reactor provided with an electric stirrer, a thermometer, a reflux water separator and a nitrogen inlet pipe, nitrogen is introduced, heating, stirring and refluxing are carried out, and the reaction is carried out for 12 hours by using nitrogen purging, so as to obtain the product.

Example 11 lubricity testing

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/FDIS12156-1 (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^-1Specific properties of hydrorefined diesel fuels having respective worn-spot diameters of 640 μm and 545 μm are shown in Table 2.

TABLE 2 physicochemical properties of diesel fuel

The antiwear agents prepared in the examples and comparative examples of the present invention were added to low sulfur diesel oil to perform diesel oil lubricity tests, and the test results are shown in table 3.

TABLE 3 improvement of lubricity of diesel fuel by antiwear product

From Table 3, it can be seen that when biodiesel is directly used as diesel antiwear agent, it has almost no effect when the additive amount is very small, and the lubricating property of low-sulfur diesel can be greatly improved by adding the product of the invention with the same amount or even smaller amount. Therefore, the diesel antiwear agent provided by the invention can well improve the lubricity of low-sulfur diesel. Especially, the unexpected effect of improving the lubricating property of the base diesel oil by the reaction product of the alkenyl succinic anhydride reaction intermediate, methanol and ethanol is most obvious and is far better than the effect of improving the lubricating property of the base diesel oil by the reaction product of the alkenyl succinic anhydride reaction intermediate, n-propanol and n-pentanol.

Example 12 Corrosion test

This example shows the corrosive effect of the products of examples 1-3 and the additives of comparative examples 1 and 2 added to diesel fuel in an amount of 200 mg/kg, as shown in Table 4^-1The test method is GB/T11143.

TABLE 4 improvement of diesel corrosion performance by antiwear agents

As can be seen from Table 4, the antiwear agent of the present invention provides a great improvement in diesel fuel rust.

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 are within the protection scope of the technical solution of the present invention.