A modified castor oil diesel anti-wear agent, a method for preparing the same, and a diesel composition

Abstract

The present invention relates to a diesel anti-wear agent, its preparation method and diesel composition containing the anti-wear agent, the diesel anti-wear agent comprising a castor oil modified product, in particular an acid ester compound generated by the reaction of castor oil with a dibasic acid or an acid anhydride. The diesel anti-wear agent provided by the present invention has the advantages of easy availability of raw materials, simple production, small dosage in diesel, good effect and great reduction of the use cost of diesel anti-wear agent.

Description

Technical Field

[0001] This invention relates to the field of fuels, and more specifically, to a diesel anti-wear agent, its preparation method, and a diesel composition thereof. Background Technology

[0002] With increasing global attention to environmental issues, the production of high-quality clean energy has become the development direction of the modern oil refining industry, leading to progressively higher standards for diesel production. This clean diesel is characterized by low aromatic content, high cetane number, light distillate, low sulfur, and low nitrogen. Sulfur is the most harmful element increasing atmospheric pollutant levels, thus requiring strict control of sulfur compound content in diesel fuel. Currently, clean diesel is mainly produced using a hydrogenation process, which removes sulfur compounds while also reducing nitrogen and oxygen compounds. It is known that the lubricity of diesel fuel depends primarily on the content of anti-wear impurities; polycyclic aromatic hydrocarbons, oxygen-containing impurities, and nitrogen-containing impurities are very effective anti-wear agents. Lower nitrogen and oxygen compound content reduces the lubricity of diesel fuel itself, leading to fuel pump wear and failure.

[0003] Because low-sulfur diesel oil has poor lubricity, it and ultra-low-sulfur diesel oil are usually treated with lubricating additives (anti-wear agents) to improve their lubrication performance. This method has advantages such as low cost, flexible production, and low pollution, and has received widespread attention in industry.

[0004] Existing industrially used low-sulfur diesel anti-wear agents mainly include two types: acidic and esteric. Acidic anti-wear agents primarily consist of long-chain unsaturated fatty acids such as oleic acid, linoleic acid, and linolenic acid, with typical products derived from refined tall oil fatty acids. CN108018100A discloses the preparation method and application of acidic anti-wear agents mainly composed of unsaturated fatty acids (saturated fatty acid content not exceeding 2.5%). Ester-type anti-wear agents are products of the esterification reaction of the aforementioned fatty acids with polyols. WO9417160A1 discloses the use of oleic acid monoglyceride as a diesel lubricating additive.

[0005] While using fatty acid-based anti-wear agents to address diesel lubrication issues is relatively low-cost, the increasing stringency of diesel emission standards and deteriorating lubricity lead to problems such as excessive dosage, resulting in excessive acidity and increased corrosion risk. Using fatty acid ester-based anti-wear agents, although requiring less dosage, also carries the risks of higher costs and emulsification / clouding of the diesel fuel upon contact with water.

[0006] Castor oil is a vegetable oil extracted from the seeds of the castor bean plant (Castorata cylindrica), belonging to the Euphorbiaceae family. It has a saponification value of 176–186 mg KOH / g and an iodine value of 82–90 g I₂ / 100g. Global castor oil production is approximately 550,000 tons, primarily produced in India and Brazil. Castor oil is the only naturally occurring vegetable oil containing hydroxyl groups. The main components of castor oil are triglycerides of higher fatty acids. The most abundant fatty acid in castor oil is ricinoleic acid (9-enyl-12-hydroxyoctadecanoic acid), accounting for 89% of the total fatty acid mass. Other components include linoleic acid (4.2%), oleic acid (3.0%), stearic acid (1.0%), palmitic acid (1.0%), linolenic acid (0.3%), and dihydroxystearic acid (0.7%). The glyceride composition is 68.2% triricinolein, 28.0% diricinolein, 2.9% monoricinolein, and 0.9% nonricinolein.

[0007] EP0605857A1 discloses the application of vegetable oils, especially castor oil, as anti-wear agents for low-sulfur diesel fuel. However, the effect of using triglyceride compounds such as vegetable oils as anti-wear agents for diesel fuel is poor, and the amount added is relatively large.

[0008] CN1234825C discloses the application of products obtained by reacting vegetable oil (including castor oil) with polyols, alkanolamines, and polyamine compounds as diesel anti-wear agents. For example, the application of a mixture of monoglycerides, diglycerides, and triglycerides obtained by alcoholysis of vegetable oil (triglycerides) and glycerol (glycerol) as a diesel anti-wear agent is described. However, this method not only requires catalysts and high-temperature reactions, but also results in high levels of free glycerol and catalysts in the product, making it difficult to process and increasing the risk of emulsification in diesel fuel.

[0009] CN113845946A discloses a fuel additive and its application as a diesel anti-wear agent. The preferred embodiment of the fuel additive is a monoester compound generated by the reaction of methyl ricinoleate with a dicarboxylic acid or anhydride. Although this type of compound has a significant anti-wear effect, the reactant methyl ricinoleate needs to be prepared from castor oil, which increases the cost and reduces the yield. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the prior art and provide a modified castor oil diesel anti-wear agent, its preparation method, and a diesel composition containing the anti-wear agent.

[0011] In a first aspect, the present invention provides a modified castor oil diesel anti-wear agent, comprising compounds of structural formula (I) and / or structural formula (II) and / or structural formula (III):

[0012] (I) Castor oil-based tris(diacid) monoester:

[0013]

[0014] (II) Castor oil-based diacid monoester:

[0015]

[0016] (III) Castor oil mono(diacid) monoester:

[0017]

[0018] Where R is C0~C 22 C2 to C are preferred. 16 More preferably, it is a C2-C8 hydrocarbon group (represented as a single bond when R is C0), wherein the hydrocarbon group can be alkylene, alkenylene, alkyl-substituted alkylene, alkyl-substituted alkenylene, alkenyl-substituted alkylene, alkenyl-substituted alkenylene, cycloalkylene, alkyl-substituted cycloalkylene, cycloalkylene, alkyl-substituted cycloalkylene, phenylene, alkyl-substituted phenylene, etc. R is further preferably vinylene, methylcyclohexene, phenylene, cyclohexylene, etc.

[0019] The diesel anti-wear agent may contain one or more compounds of structural formula (I), structural formula (II), and structural formula (III), preferably with a content of structural formula (I) ≥50% (by mass), more preferably ≥60%, more preferably ≥70%, and most preferably ≥75%. According to a specific embodiment of the present invention, the anti-wear agent product contains 80% (by mass) of structural formula (I), 15% (by mass) of structural formula (II), and 5% (by mass) of structural formula (III).

[0020] Secondly, the present invention provides a method for preparing the above-mentioned modified castor oil diesel anti-wear agent, the method comprising: reacting castor oil with a dibasic acid or anhydride at a molar ratio of 1:1 to 1:10, preferably 1:2-8, more preferably 1:3-5.

[0021] The inventors of this application have discovered that by reacting castor oil with a diacid or its anhydride, the hydroxyl group on ricinoleic acid reacts with the carboxyl group of the diacid or its anhydride to generate an ester group. By controlling the molar ratio of the two, castor oil diacid monoester compounds and mixtures thereof with structural formulas (I) and / or (II) and / or (III) can be obtained. These compounds can be used as diesel anti-wear agents, with significantly better effects than existing fatty acid type and fatty acid ester type anti-wear agents. Moreover, the production process is environmentally friendly with no waste emissions and low usage costs.

[0022] The dicarboxylic acid or its anhydride is selected from C2 to C24, preferably C4 to C18, and more preferably C4 to C18. 10A hydrocarbon-based dicarboxylic acid or its anhydride, wherein the hydrocarbon group may be saturated or unsaturated, and may be unsubstituted or substituted.

[0023] The hydrocarbon group may be selected from alkylene, alkenylene, alkyl-substituted alkylene, alkyl-substituted alkenylene, alkenyl-substituted alkylene, alkenyl-substituted alkenylene, cycloalkylene, alkyl-substituted cycloalkylene, cycloalkylene, alkyl-substituted cycloalkylene, phenylene, and alkyl-substituted phenylene. The hydrocarbon group is preferably vinylene, methylcyclohexene, phenylene, or cyclohexylene.

[0024] Specifically, the saturated chain dicarboxylic acid can be selected from one or more of the following compounds: oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, methyl succinic acid, etc.

[0025] The saturated cyclic dicarboxylic acid is preferably 1,2-cyclopentadicarboxylic acid, 1,3-cyclopentadicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,2-cyclohexanediacetic acid, methylhexahydrophthalic acid, 1-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, etc.

[0026] The unsaturated chain dicarboxylic acid can be selected from maleic acid, fumaric acid, cis-methylbutenedioic acid, trans-methylbutenedioic acid, dimethylmaleic acid, itaconic acid (methylene succinic acid, methylene succinic acid), pentenedioic acid, dodecenyl succinic acid, etc.

[0027] The unsaturated cyclic dicarboxylic acid is selected from phthalic acid, terephthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, 4-cyclohexene-1,2-dicarboxylic acid, 4-methyl-4-cyclohexene-1,2-dicarboxylic acid, 3-methyl-4-cyclohexene-1,2-dicarboxylic acid, etc.

[0028] The preferred dicarboxylic acid is phthalic acid, tetrahydrophthalic acid, or methyltetrahydrophthalic acid.

[0029] The saturated dicarboxylic acid anhydride is selected from succinic anhydride, methylsuccinic anhydride, glutaric anhydride, adipic anhydride, etc. It can also be selected from: 1,2-cyclopropanedicarboxylic anhydride (CAS 5617-74-3), 1,2-cyclopentanedicarboxylic anhydride (CAS 5763-49-5), 1,3-cyclopentanedicarboxylic anhydride (CAS 6054-16-6), 1,2-cyclohexanedicarboxylic anhydride (CAS 85-42-7), hexahydrophthalic anhydride (CAS 13149-00-3), 1,1-cyclohexanediacetic anhydride (CAS 1010-26-0), 1-methyl-1,2-cyclohexanedicarboxylic anhydride (CAS 25550-51-0), 3-methyl-1,2-cyclohexanedicarboxylic anhydride (CAS 57110-29-9), 4-methyl-1,2-cyclohexanedicarboxylic anhydride (CAS 19438-60-9), methylhexahydrophthalic anhydride (CAS 34090-76-1), etc.

[0030] The unsaturated anhydride can be selected from maleic anhydride, 2,3-dimethylmaleic anhydride, citraconic anhydride, itaconic anhydride, pentene anhydride, etc. It can also be selected from: phthalic anhydride (85-44-9), tetrahydrophthalic anhydride (CAS 2426-02-0), tetrahydrophthalic anhydride (CAS 26266-63-7), tetrahydrophthalic anhydride (CAS 935-79-5), tetrahydrophthalic anhydride (CAS 13149-03-6), tetrahydrophthalic anhydride (CAS 85-43-8), methyltetrahydrophthalic anhydride (CAS 19428-64-3), methyltetrahydrophthalic anhydride (CAS 5333-84-6), methyltetrahydrophthalic anhydride (CAS 3425-89-6), methyltetrahydrophthalic anhydride (CAS 11070-44-3), methyltetrahydrophthalic anhydride (CAS 26590-20-5), etc.

[0031] The preferred acid anhydride is one or more of the following: maleic anhydride, citraconic anhydride, itaconic anhydride, succinic anhydride, dodecenylsuccinic anhydride, phthalic anhydride, 1,2-cyclohexanedicarboxylic anhydride (hexahydrophthalic anhydride), tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride.

[0032] According to the method of the present invention, a catalyst may or may not be added during the reaction. The catalyst can be an acid catalyst, such as one or more of sulfuric acid, hydrochloric acid, p-toluenesulfonic acid, phosphoric acid, boric acid, and acidic ion exchange resin; an ionic liquid catalyst, such as 1-butylpyridine / AlCl4 ionic liquid; an inorganic salt solid-phase catalyst, such as one or more of FeCl3 and AlCl3; a molecular sieve catalyst, such as one or more of ZSM-5, HZSM-5, and Al-MCM-41; or a heteropolyacid catalyst, such as PW 12 / MCM-41、 SiW 12 One or more of / MCM-41, etc.; can be used with solid superacid catalysts, such as SO4. 2- / ZrO2-TiO2, etc.; can be used with alkaline catalysts such as NaOH, KOH, sodium methoxide, solid superalkali, NaH, etc.

[0033] According to the method of the present invention, a solvent may or may not be added during the reaction. The solvent may be a hydrocarbon such as alkanes and aromatics, such as petroleum ether, gasoline, toluene, xylene, etc.

[0034] According to the method of the present invention, after the reaction is completed, the unreacted acid or acid anhydride is separated by means of water washing, low temperature sedimentation, centrifugation, vacuum distillation, molecular distillation, thin film evaporation and other treatment methods.

[0035] According to the method of the present invention, the reaction temperature is 50-250℃, preferably 60℃-180℃, more preferably 60-150℃, the reaction time is 0.1-10hr, preferably 1-8hr, more preferably 2-6hr, and the reaction pressure can be atmospheric pressure or under a certain pressure.

[0036] According to the method of the present invention, when the molar ratio of castor oil to diacid or anhydride is 1:3 to 10, the reaction product is mainly a compound of structural formula (I); when the molar ratio of castor oil to diacid or anhydride is 1:1.5 to 3, the reaction product is mainly a compound of structural formula (II); and when the molar ratio of castor oil to diacid or anhydride is 1:0.1 to 1.5, the reaction product is mainly a compound of structural formula (III). Based on the experimental results of the present invention, the anti-wear effect is optimal when the reaction product is mainly a compound of structural formula (I).

[0037] In addition to the compounds with structural formulas (I), (II), and (III), the reaction products may also contain small amounts of unreacted castor oil and castor oil-based tris(diacid) diester, castor oil-based di(diacid) diester, and castor oil-based mono(diacid) diester (collectively referred to as castor oil-based dicarboxylic acid diester). These compounds do not have significant anti-wear effects and have virtually no impact on the performance of diesel fuel; therefore, they do not need to be separated from the products. Under normal circumstances, using anhydrides as raw materials, under the reaction conditions of this invention, castor oil-based dicarboxylic acid diester is basically not generated or only a small amount is generated. Using diacids as raw materials, controlling the reaction at a lower temperature and for a shorter time can reduce the formation of castor oil-based dicarboxylic acid diester.

[0038] Thirdly, the present invention provides a method for improving the lubricity of diesel fuel, the method comprising adding the composition of the present invention to diesel fuel at an amount of 10 to 400 ppm, preferably 50 to 200 ppm, based on 100% by weight of diesel fuel.

[0039] Fourthly, the present invention provides a diesel composition comprising diesel fuel, and the composition of the present invention having a content of 10 to 400 ppm, preferably 50 to 200 ppm, based on 100% by weight of diesel fuel.

[0040] The diesel fuel described in this invention includes various diesel fuels, particularly low-sulfur diesel engine fuels. For example, it can be a fraction of crude oil (petroleum) processed by various refining processes in an oil refinery, such as atmospheric and vacuum distillation, catalytic cracking, catalytic reforming, coking, hydrorefining, and hydrocracking, with a distillation range between 160 and 380°C, and blended to meet the national standard GB / T 19147 for automotive diesel fuels for compression-ignition internal combustion engines.

[0041] The diesel fuel can also be second-generation biodiesel, which is derived from renewable resources such as vegetable oils and animal fats. It is typically produced in refineries using hydrotreating to hydrogenate vegetable oils, producing isomerized or non-isomerized long-chain hydrocarbons. Second-generation biodiesel may be similar in properties and quality to petroleum-based fuel oils.

[0042] The diesel fuel can also be third-generation biodiesel, which is obtained by gasification and Fischer-Tropsch technology from non-oil biomass with high cellulose content, such as sawdust, crop straw and solid waste, and microbial oils.

[0043] The diesel fuel can also be coal liquefaction diesel (CTL), referring to diesel engine fuel obtained by coal liquefaction or direct coal liquefaction. It can also be a blend of petroleum-based diesel fuel with added oxygenated diesel blending components. These oxygenated diesel blending components are oxygenated compounds or mixtures of oxygenated compounds that can be blended with various diesel engine fuels to meet certain specifications. They are typically alcohols and ethers or mixtures thereof, such as ethanol, polyoxymethylene dimethyl ethers (PODEn, DMMn, or OME), di-tert-butyl glycerol ether, and tri-tert-butyl glycerol ether.

[0044] Depending on the application requirements, the diesel composition of the present invention may also contain one or more of the following additives: phenolic antioxidants, fatty acid or fatty acid ester type diesel anti-wear agents, high molecular weight amine type ashless dispersants, flow improvers, cetane number improvers, metal passivators, antistatic agents, corrosion inhibitors, rust inhibitors, and demulsifiers.

[0045] The diesel anti-wear agent of this invention uses readily available raw materials and is easy to produce. Its effect is surprisingly superior to traditional fatty acid-based or fatty acid ester-based anti-wear agents. It can significantly improve the lubricity of low-sulfur diesel oil, greatly reduce the amount added, and further reduce the cost of use. Attached Figure Description

[0046] Figure 1 The infrared spectrum of the castor oil-based trimaleic acid monoester obtained in Example 1 is shown below.

[0047] wave number 3460cm -1 The peak represents the stretching vibration of -OH, with a combined wavenumber of 1670 cm⁻¹. -1 The peak represents the stretching vibration of the carboxyl carbonyl group (C=O), referring to the carboxyl group (-COOH); wavenumber 1735 cm⁻¹. -1 The peak represents the stretching vibration of the carbonyl group in the ester (C=O), indicating the ester group (-COOR); wavenumber 3010 cm⁻¹ -1 The characteristic peak of -CH3, wavenumber 2927 cm⁻¹. -1 The characteristic vibration peak of -CH2- is consistent with the infrared spectrum of castor oil-based trimaleic acid monoester.

[0048] Figure 2 The mass spectrum of castor oil-based trimaleic acid monoester obtained in Preparation Example 1 is shown, where m / z = 1249.76 is C. 69 H 110 O 18 The +Na signal peak appears in the mass spectrometry results because the castor oil-based trimaleic acid monoester structure contains ester and carboxyl groups, which are readily binding sites for Na protons. 69 H 110 O18 The signal peak for +Na was observed, while the theoretical relative molecular mass of castor oil-based trimaleic acid monoester is 1226 g / mol. The mass spectrometry results are consistent with the theoretical molecular mass of castor oil-based trimaleic acid monoester. m / z = 1151.76 indicates C... 65 H 108 O 15 The +Na signal peak appears in the mass spectrometry results because the castor oil-based dimaleic acid monoester structure contains ester and carboxyl groups, which are readily binding sites for Na protons. 65 H 108 O 15 The +Na signal peak was observed, while the theoretical relative molecular mass of castor oil-based dimaleic acid monoester is 1128 g / mol. The mass spectrometry results are consistent with the theoretical molecular mass of castor oil-based dimaleic acid monoester. m / z = 1053.76 indicates C... 61 H 106 O 12 The +Na signal peak appears in the mass spectrometry results because the castor oil-based maleic acid monoester structure contains ester and carboxyl groups, which are readily binding sites for Na protons. 61 H 106 O 12 The signal peak of +Na was observed, while the theoretical relative molecular mass of castor oil-based monomaleic acid ester is 1030 g / mol, and the mass spectrometry analysis results are consistent with the theoretical molecular mass of castor oil-based monomaleic acid ester. Detailed Implementation

[0049] The present invention will be described in detail below through embodiments. It should be understood that the present invention can have various variations in different implementations, all of which do not depart from the scope of the present invention, and the descriptions and illustrations therein are for illustrative purposes only and not intended to limit the present invention.

[0050] The method for calculating the composition content in the product is as follows: In a mass spectrum, the peak intensity of the target molecule structure divided by the peak intensities of all the product compounds is the yield of the target molecule in the product.

[0051] Preparation Example 1

[0052] Preparation of castor oil-based trimaleic acid monoester:

[0053] In a 1000 mL reactor equipped with an electric stirrer and a thermometer, 464 g of castor oil (99%, produced by Sinopharm Group Co., Ltd.) and 161 g of maleic anhydride (99.5%, produced by Aladdin Reagent Co., Ltd.) were added. The molar ratio of castor oil to maleic anhydride was approximately 1:3.3. The mixture was heated and stirred until it reached 85 °C. After reacting for 1 hour, the temperature was increased to 120 °C and the reaction continued for another 4 hours. The reaction product was subjected to molecular distillation at 110 °C and an absolute pressure of 10 Pa. Approximately 583 g of the recombinant molecularly distilled fraction was collected as the product. The reaction process is shown in Reaction Equation 1.

[0054] The infrared spectrum of castor oil trimaleic acid monoester is as follows: Figure 1 As shown, it has characteristic structures with carboxyl and ester groups; the mass spectrum of castor oil trimaleic acid monoester as the main component is shown below. Figure 2 As shown, the total content of castor oil-based maleic acid monoester is approximately 92%, the content of castor oil-based trimaleic acid monoester is 80%, the content of castor oil-based dimaleic acid monoester is 15%, and the content of castor oil-based monomaleic acid monoester is 5%.

[0055]

[0056] Preparation Example 2

[0057] Preparation of castor oil tris(methyltetrahydrophthalic acid) ester:

[0058] In a 1000mL reactor equipped with an electric stirrer and a thermometer, 500g of castor oil (99%, purchased from Sinopharm Group Co., Ltd.) and 267.5g of methyltetrahydrophthalic anhydride (98%, purchased from Beijing Innocare Technology Co., Ltd.) were added. The molar ratio of castor oil to methyltetrahydrophthalic anhydride was approximately 1:3. The mixture was heated and stirred to 135℃, and after reacting for 4 hours, a total of 762.9g of anti-wear agent product with castor oil trimethyl(methyltetrahydrophthalic acid) monoester as the main component was obtained.

[0059] The preparation process of castor oil tris(methyltetrahydrophthalic acid) monoester is shown in reaction formula 2.

[0060]

[0061] Preparation Example 3

[0062] Preparation of castor oil triterpenoid (phthalic acid):

[0063] In a 1000mL reactor equipped with an electric stirrer and a thermometer, 500g of castor oil (99%, purchased from Sinopharm Group Co., Ltd.) and 277.9g of phthalic anhydride (98%, purchased from Beijing Innocare Technology Co., Ltd.) were added. The molar ratio of castor oil to phthalic anhydride was approximately 1:3.5. The procedure was as follows: First, the phthalic anhydride was heated to 135℃ until it was completely melted into a liquid state. Then, castor oil was added, and the temperature was raised to 180℃. After reacting for 4 hours, a total of 772.3g of anti-wear agent product with castor oil triterpenoids (phthalic acid) as the main component was obtained.

[0064] The preparation process of castor oil triterpenoid (phthalic acid) ester is shown in reaction formula 3.

[0065]

[0066] Preparation Example 4

[0067] Preparation of castor oil tris(cyclohexanedicarboxylic acid) ester:

[0068] In a 1000mL reactor equipped with an electric stirrer and a thermometer, 500g of castor oil (99%, purchased from Sinopharm Group Co., Ltd.) and 247.8g of hexahydrophthalic anhydride (1,2-cyclohexanedicarboxylic anhydride, 99% by mass, purchased from Beijing Innocare Technology Co., Ltd.) were added. The molar ratio of castor oil to hexahydrophthalic anhydride was approximately 1:3. The operation procedure was as follows: first, the hexahydrophthalic anhydride was heated to 50℃ to completely melt it into a liquid state, then castor oil was added, and the temperature was raised to 130℃ for 4 hours to obtain a total of 742.3g of anti-wear agent product with castor oil tris(cyclohexanedicarboxylic acid) ester as the main component.

[0069] The preparation process of castor oil tris(cyclohexanedicarboxylic acid) ester is shown in reaction formula 4.

[0070]

[0071] Preparation Example 5

[0072] Following the method of Preparation Example 1, the molar ratio of castor oil to maleic anhydride was approximately 1:2, and other conditions were the same. An anti-wear agent product with castor oil-based dimaleic acid monoester as the main product was obtained, wherein the total content of castor oil-based maleic acid monoester was approximately 88%, the content of castor oil-based trimaleic acid monoester was approximately 38%, the content of castor oil-based dimaleic acid monoester was approximately 46%, and the content of castor oil-based monomaleic acid monoester was approximately 15%.

[0073] Preparation Example 6

[0074] Following the method of Preparation Example 1, the molar ratio of castor oil to maleic anhydride was approximately 1:1, and other conditions were the same. An anti-wear agent product with castor oil-based monomaleic acid ester as the main product was obtained, wherein the total content of castor oil-based monomaleic acid ester was approximately 76%, the content of castor oil-based trimaleic acid ester was 7%, the content of castor oil-based dimaleic acid ester was 12%, and the content of castor oil-based monomaleic acid ester was 81%.

[0075] Comparative Preparation Example 1

[0076] Preparation of methyl castor oil maleic acid monoester:

[0077] In a 500 mL reactor equipped with an electric stirrer, thermometer, reflux condenser, and nitrogen inlet, 250 g of methyl ricinoleate (75% by mass, Shanghai Aladdin Biochemical Technology Co., Ltd.) and 78.5 g of maleic anhydride (99% by mass, Shanghai Aladdin Biochemical Technology Co., Ltd.) were added. The molar ratio of methyl ricinoleate to maleic anhydride was approximately 1:1. Nitrogen gas was introduced for 5–10 minutes, and the mixture was heated and stirred to 100 °C. The mixture was then refluxed for 4 hours to obtain a total of 323.9 g of product with methyl ricinoleate-based maleic acid monoester as the main component.

[0078] Contrast agent 1

[0079] Castor oil disclosed in EP0605857A1 was used as an anti-wear agent.

[0080] Contrast agent 2

[0081] The methyl castor oil maleate monoester obtained in Comparative Preparation Example 1 was used as an anti-wear agent.

[0082] Contrast agent 3

[0083] KMJ-031 is an acidic anti-wear agent with oleic acid and linoleic acid as its main components (produced by Xinjiang Dasen Chemical Co., Ltd.).

[0084] Test case

[0085] The product and contrast agent obtained in the preparation example were added to diesel fuel at a certain dosage, and the lubrication performance in diesel fuel was tested. Diesel fuel A was obtained from Sinopec Yanshan Branch. Its physicochemical properties are shown in Table 1, and the test results are shown in Table 2.

[0086] Table 1 Basic Physicochemical Properties of Diesel Oil

[0087]

[0088]

[0089] The lubricity of diesel fuel was determined by measuring the wear scar diameter (WSD) at 60°C on a high-frequency reciprocating tester (HFRR, PCS Instruments, UK) according to the SH / T 0765 method. The results were reported as WS1.4 after correcting for the effects of temperature and humidity.

[0090] The wear scar diameter WS1.4 of diesel fuel before and after additive addition is shown in Table 3. The smaller the wear scar diameter, the better the lubricity of the diesel fuel. Currently, most diesel fuel standards worldwide, such as European standard EN 590, Chinese automotive diesel fuel standard GB 19147, and Beijing municipal standard DB 11 / 239, use a wear scar diameter of less than 460 μm (60℃) as the criterion for acceptable diesel fuel lubricity.

[0091] Table 2 Evaluation of the lubricating performance of diesel fuel with additives

[0092]

[0093]

[0094] As can be seen from Table 3, the additives provided by the present invention greatly improve the lubricity of diesel fuel. Compared with Examples 4 and 6, Example 1 has a better effect, indicating that the anti-wear composition based on structural formula (I) is better than the composition based on the structure shown in structural formula (II) or structural formula (III).

[0095] Compared to existing industrial anti-wear agent contrast agent 3, the amount of anti-wear agent added in this invention can be greatly reduced, which lowers the cost of adding additives and also reduces the risk of side effects after adding additives.

[0096] Compared with Comparative Agent 2 (methyl ricinoleate-based maleic acid monoester anti-wear agent product), this invention not only has better anti-wear effect but also has a significant cost advantage. This invention uses castor oil directly as a raw material, resulting in low cost; while methyl ricinoleate requires esterification or transesterification reactions, which involve a long preparation process and high energy consumption. Therefore, the anti-wear agent of this invention, while possessing significantly superior anti-wear performance, also features readily available raw materials, low preparation cost, short process flow, low risk, and is clean and environmentally friendly.

Claims

1. A diesel composition comprising diesel oil and a modified castor oil diesel anti-wear agent, said modified castor oil diesel anti-wear agent comprising a mixture of a compound having structural formula (I), a compound having structural formula (II), and a compound having structural formula (III): (I) Castor oil-based trimaleic acid monoester: (II) Castor oil-based dimaleic acid monoester: (III) Castor oil-based monomaleic acid ester: Where R stands for vinylidene; The anti-wear agent contains ≥75% by mass of a compound having structural formula (Ⅰ).

2. The diesel composition according to claim 1, wherein the anti-wear agent content is 10-400 ppm based on 100% diesel oil mass.

3. The diesel composition according to claim 2, wherein, The anti-wear agent content is 50~200ppm.

4. The diesel composition according to claim 1, wherein, The diesel fuel has a distillation range of 160~380℃.

5. The diesel composition according to claim 1, wherein, The diesel fuel is selected from one of the following: blended diesel fuel (made by adding oxygenated diesel fuel to petroleum-based diesel), low-sulfur diesel engine fuel, second-generation biodiesel, third-generation biodiesel, and coal liquefaction diesel.

6. A method for improving the lubricity of diesel fuel, comprising: A modified castor oil diesel anti-wear agent is added to diesel fuel, the modified castor oil diesel anti-wear agent comprising a compound having structural formula (I), a compound having structural formula (II), and a compound having structural formula (III): (I) Castor oil-based trimaleic acid monoester: (II) Castor oil-based dimaleic acid monoester: (III) Castor oil-based monomaleic acid ester: Where R stands for vinylidene; The anti-wear agent contains ≥75% by mass of a compound having structural formula (Ⅰ).

7. According to the method of claim 6, the anti-wear agent is added to the diesel fuel at an amount of 10 to 400 ppm, based on 100% of the diesel fuel mass.

8. The method according to claim 7, wherein the anti-wear agent is added to the diesel fuel at an amount of 50 to 200 ppm.

9. The method according to claim 6, wherein, The diesel fuel has a distillation range of 160~380℃.

10. The method according to claim 6, wherein, The diesel fuel is selected from one of the following: blended diesel fuel (made by adding oxygenated diesel fuel to petroleum-based diesel), low-sulfur diesel engine fuel, second-generation biodiesel, third-generation biodiesel, and coal liquefaction diesel.

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