Preparation method of methyl oleate succinic anhydride, diesel oil additive and preparation method and application of diesel oil additive

Abstract

The invention relates to a preparation method of methyl oleate succinic anhydride, which comprises the following steps: reacting a substrate containing methyl oleate with maleic anhydride under the condition of addition reaction to obtain a methyl oleate succinic anhydride reaction intermediate; and carrying out molecular distillation on the methyl oleate succinic anhydride reaction intermediate to obtain refined methyl oleate succinic anhydride. The invention further relates to a diesel oil additive obtained through esterification reaction of the refined methyl oleate succinic anhydride and a preparation method and application of the diesel oil additive. By utilizing the characteristics of low operation temperature and short heating time of molecular distillation, the methyl oleate succinic anhydride reaction intermediate is subjected to molecular distillation refining, a high-purity methyl oleate succinic anhydride platform compound is provided, and when the high-purity methyl oleate succinic anhydride platform compound is used for esterification reaction, the yield is high, and the yield is high. And the yield of methyl oleate succinic acid monoester in the obtained product is greatly improved.

Description

Technical Field

[0001] The invention belongs to the field of oil additives, and in particular relates to a preparation method of methyl oleate succinic anhydride and a diesel additive as well as a preparation method and use thereof. Background Art

[0002] In order to avoid diesel engine failure due to fuel wear, adding diesel anti-wear agent to low sulfur diesel is a simple and effective method. Diesel anti-wear agent is dissolved in diesel and mainly relies on physical and chemical adsorption to form a strong directional adsorption film on the friction surface for lubrication. For effective adsorption and lubrication, it is required that not only the diesel anti-wear agent molecules have polarity, but also that its molecular configuration is conducive to the formation of a high resistance protective film. Therefore, diesel anti-wear agent is generally a long-chain linear molecule with polar groups.

[0003] The diesel lubricity improvers currently used in China include fatty acid-type lubricity improvers, but such lubricity improvers have compatibility issues with other additives in diesel, for example, fatty acids react with nitrogen compounds in diesel detergents, resulting in a decrease in the performance of both anti-wear agents and detergents. Branched carboxylic acids are also reported to have good lubricity, but carboxylic acid-type anti-wear agents are prone to clogging fuel filters and may also corrode metals due to their strong acidity.

[0004] Methyl oleate is an unsaturated higher fatty acid ester and an important chemical raw material. Methyl oleate can be separated from biodiesel, has abundant sources, is cheap and easy to obtain. The addition product of methyl oleate and unsaturated anhydride can be used as a platform compound to further synthesize compounds with different functional groups or different uses. For example, CN112779065B provides a technical solution of alkenyl succinic acid monoester compound as a diesel antiwear agent, in which methyl oleate and unsaturated anhydride are first subjected to Adel-ene reaction to prepare alkenyl succinic anhydride, and then alkenyl succinic anhydride and fatty alcohol are subjected to esterification to obtain an antiwear agent product. However, the purity of alkenyl succinic anhydride in the alkenyl succinic anhydride product prepared by the above technical solution is low, so that the effective content of the esterification reaction product is small, and the difficulty of separation and purification of the esterification product is also increased. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing high-purity methyl oleate succinic anhydride.

[0006] In order to achieve the above object, the first aspect of the present invention provides a method for preparing methyl oleate succinic anhydride, which method comprises the following steps:

[0007] (1) reacting a substrate containing methyl oleate with maleic anhydride under addition reaction conditions to obtain a methyl oleate succinic anhydride reaction intermediate;

[0008] (2) molecularly distilling the methyl oleate succinic anhydride reaction intermediate to obtain refined methyl oleate succinic anhydride.

[0009] Optionally, the substrate containing methyl oleate is biodiesel or methyl oleate; the content of methyl oleate in the biodiesel is 30-100wt%, preferably 50-95wt%, and further preferably 60-90wt%; the conditions of the addition reaction include: the reaction temperature is 100-280°C, preferably 180-240°C; the reaction time is 1-20h, preferably 6-12h; the molar ratio of the substrate containing methyl oleate to maleic anhydride is 1:(0.1-10), preferably 1:(0.5-5).

[0010] Optionally, an antioxidant is added to the reaction of step (1), and the amount of the antioxidant added is 0.01-5%, preferably 0.05-2%, and more preferably 0.1-1%, based on the total weight of the substrate containing methyl oleate and the maleic anhydride; the antioxidant is selected from one or more of tert-butylhydroquinone, gallic acid C1-C18 esters, phenolic antioxidants, aromatic amine antioxidants, and heterocyclic antioxidants; the phenolic antioxidant is selected from 3-(3,5-di-tert-butyl-4-hydroxyphenyl) acrylate, antioxidant 1010 , antioxidant 2246, antioxidant 1076 and antioxidant 300; the aromatic amine antioxidant is selected from one or more of N',N-diphenyl-p-phenylenediamine, N,N'-hexamethylene-bis-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide, phenothiazine, antioxidant DNP, antioxidant H and antioxidant 4010; the heterocyclic antioxidant is selected from one or more of benzotriazole, alkyl-substituted imidazoline, 2-mercaptobenzothiazole and 2,5-dimercapto-1,3,4-thiadiazole and their derivatives.

[0011] Optionally, the molecular distillation includes one-step molecular distillation; the cut point of the one-step molecular distillation is any temperature between 30-500°C, preferably any temperature between 50-300°C, and further preferably any temperature between 80-250°C; the pressure during the one-step molecular distillation is 0.05-50Pa, preferably 0.1-20Pa.

[0012] Optionally, the molecular distillation includes continuous primary molecular distillation and secondary molecular distillation; the cut point of the primary molecular distillation is any temperature between 30-300°C, preferably any temperature between 50-250°C; the pressure of the primary molecular distillation is 0.05-50Pa, preferably 0.1-20Pa; the cut point of the secondary molecular distillation is any temperature between 50-500°C, preferably any temperature between 100-300°C; the pressure of the secondary molecular distillation is 0.01-30Pa, preferably 0.1-20Pa.

[0013] Optionally, the molecular distillation includes a one-step molecular distillation, and the light components of the one-step molecular distillation are returned to step (1) as raw materials for the addition reaction; or the molecular distillation includes continuous primary molecular distillation and secondary molecular distillation, and the light components of the primary molecular distillation and / or the heavy components of the secondary molecular distillation are returned to step (1) as raw materials for the addition reaction.

[0014] Optionally, the content of methyl oleyl succinic anhydride in the refined methyl oleyl succinic anhydride is 90-99.9wt%, preferably 95-99.9wt%.

[0015] A second aspect of the present invention provides a method for preparing a diesel additive, the method comprising:

[0016] The above-mentioned preparation method is used to prepare refined methyl oleate succinic anhydride;

[0017] Then, the refined methyl oleyl succinic anhydride is subjected to an esterification reaction with a hydroxyl-containing compound to obtain an esterification product; the content of methyl oleyl succinic acid monoester in the esterification product is 90-100wt%, preferably 92-100wt%.

[0018] Optionally, the conditions of the esterification reaction include: a temperature of 40-180°C, preferably 50-120°C; a reaction time of 10 min-8 h, preferably 0.5-2 h; a molar ratio of the methyl oleate succinic anhydride to the hydroxyl-containing compound of 1:(0.5-1.2), preferably 1:(0.8-1.1).

[0019] Optionally, the hydroxyl-containing compound is selected from one or more of aliphatic alcohols, alicyclic alcohols, aromatic alcohols, phenols and alcohol ethers having 1 to 30 carbon atoms, preferably one or more of aliphatic alcohols, alicyclic alcohols, aromatic alcohols, phenols and alcohol ethers having 1 to 18 carbon atoms; the aliphatic alcohol is a saturated or unsaturated, normal or isomeric aliphatic alcohol; the alicyclic alcohol is selected from one or more of cyclobutanol, cyclopentanol, cyclohexanol, 3-cyclopentene-1-ol, 2-cyclohexenol and 3-cyclohexene-1-methanol; the aromatic alcohol is selected from one or more of benzyl alcohol, phenylethyl alcohol and phenylpropanol; the phenol is selected from one or more of propylphenol, butylphenol, pentylphenol, heptylphenol, octylphenol, nonylphenol, decylphenol and dodecylphenol; the structural formula of the alcohol ether is R 2 [OR 1 ] n OH, where R 1 is selected from -CH2CH2-, -CH(CH3)CH2-, -CH2CH(CH3)-; n is selected from an integer of 1-10; R 2 Selected from substituted or unsubstituted C1-C 18 of hydrocarbon groups.

[0020] The third aspect of the present invention provides a diesel additive prepared according to the second aspect of the present invention.

[0021] The fourth aspect of the present invention provides a method for preparing diesel, which comprises: mixing a diesel base oil with an anti-wear agent; the anti-wear agent is the diesel additive provided by the third aspect of the present invention; the diesel additive is added to the diesel base oil in an amount of 50-400 μg / g.

[0022] Through the above technical scheme, the present invention provides a method for preparing high-purity methyl oleate succinic anhydride, by molecular distillation and refining the methyl oleate succinic anhydride reaction intermediate, the purity of the methyl oleate succinic anhydride can be increased from 30wt% to more than 90wt% by utilizing the characteristics of low molecular distillation operating temperature and short heating time. The prepared high-purity methyl oleate succinic anhydride product can be used as a platform compound, and further esterified with hydroxyl compounds such as fatty alcohols and ether alcohols to prepare high-purity, high-value-added products.

[0023] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a chromatogram of the refined methyl oleate succinic anhydride product obtained after molecular distillation in Example 1, wherein the mass fraction of methyl oleate succinic anhydride (ASA) is 94.7 wt %.

[0025] Figure 2It is a chromatogram of the methyl oleyl succinic anhydride product prepared in Comparative Example 1, wherein the mass fraction of methyl oleyl succinic anhydride (ASA) is 34 wt %.

[0026] Figure 3 3 is the mass spectrum of methyl oleyl succinate prepared in Example 1. In the figure, m / z=449.29 is the mass spectrum addition peak of the sodium ion of methyl oleyl succinate prepared in Example 1.

[0027] Figure 4 The infrared spectrum of methyl oleyl succinate of Example 1, the peaks in the figure are attributed as follows: 2800cm -1 ~3000cm -1 and 1450cm -1 The peak indicates aliphatic hydrocarbon structure; 1781cm -1 The peak represents the ester carbonyl group close to the carboxyl group; 1735 cm -1 The peak represents the ester group at the end of the long chain; 1708 cm -1 The peak represents carboxylic acid; 1217 cm -1 The nearby peaks indicate the CO structure; 3000cm -1 Nearby and 1640cm -1 The nearby peaks represent carbon-carbon double bonds.

[0028] Figure 5 This is a gas chromatogram of the esterification product prepared in Example 1, wherein the mass fraction of methyl oleyl succinate is 94%.

[0029] Figure 6 It is a gas chromatogram of the esterification product prepared in Comparative Example 1, wherein the mass fraction of methyl oleyl succinate is 43%.

[0030] Figure 7 This is the wear spot detection image of blank diesel A, where the wear spot diameter (WS1.4) is 640μm.

[0031] Figure 8 This is a wear spot detection diagram when the esterification product prepared in Example 1 is added to blank diesel A, wherein the addition amount of the esterification product prepared in Example 1 to blank diesel A is 200 mg / kg, and the wear spot diameter (WS1.4) in the wear spot detection diagram is 265 μm.

[0032] Fig. 9The figures are the effect diagrams of metal rod corrosion test, wherein a is the corrosion test metal rod of blank diesel A, and the corrosion test duration is 4 hours; b is the corrosion test metal rod of blank diesel A to which the esterification product prepared in Example 1 (the addition amount is 50 mg / kg) is added, and the corrosion test duration is 24 hours; c is the corrosion test metal rod of blank diesel A to which the esterification product prepared in Comparative Example 2 (the addition amount is 50 mg / kg) is added, and the corrosion test duration is 4 hours. DETAILED DESCRIPTION

[0033] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0034] The first aspect of the present invention provides a method for preparing methyl oleate succinic anhydride, the method comprising the following steps:

[0035] (1) reacting a substrate containing methyl oleate with maleic anhydride under addition reaction conditions to obtain a methyl oleate succinic anhydride reaction intermediate;

[0036] (2) molecularly distilling the methyl oleate succinic anhydride reaction intermediate to obtain refined methyl oleate succinic anhydride.

[0037] The invention carries out molecular distillation purification on the reaction intermediate of methyl oleyl succinic anhydride. By utilizing the characteristics of low operating temperature and short heating time of molecular distillation, the separation degree of methyl oleyl succinic anhydride is high. When the methyl oleyl succinic anhydride with high purity is used for esterification reaction, the yield of methyl oleyl succinic acid monoester in the obtained product is greatly improved.

[0038] Molecular distillation is short-path distillation, which can achieve clear separation of key components in mixtures with components of similar boiling points to ensure high yield of key components.

[0039] Wherein, the substrate containing methyl oleate is biodiesel or methyl oleate; the content of methyl oleate in the biodiesel is 30-100wt%, preferably 50-95wt%, and more preferably 60-90wt%. In some specific embodiments of the present invention, the content of methyl oleate in the biodiesel can be 60wt%, 65wt%, 73wt%, 85wt%, 90wt% or any value within the aforementioned range.

[0040] The conditions of the addition reaction include: reaction temperature of 100-280° C., preferably 180-240° C.; reaction time of 1-20 h, preferably 6-12 h; and a molar ratio of the substrate containing methyl oleate to maleic anhydride of 1:(0.1-10), preferably 1:(0.5-5).

[0041] In the present invention, the main component of the fatty acid methyl ester in the biodiesel is methyl oleate. Biodiesel is a raw material for preparing methyl oleate succinic acid monoester, which is easy to obtain, abundant and low in cost.

[0042] Methyl oleate and maleic anhydride undergo an "Alder-ene reaction" under the above-mentioned addition reaction conditions. Since there is a C=C double bond on the main chain of methyl oleate, there are two reaction sites on methyl oleate, and the obtained products also have different structures.

[0043] In the present invention, an antioxidant is added to the reaction of step (1). Under addition reaction conditions, the chemical bonds of the reactants are broken to generate active free radicals and hydroperoxides, and the decomposition reaction of hydroperoxides can also generate hydrocarbon oxygen free radicals and hydroxyl free radicals. The antioxidant can capture the generated free radicals, or promote the decomposition of hydroperoxides to prevent free radicals from initiating a chain reaction.

[0044] Wherein, based on the total weight of the substrate containing methyl oleate and the maleic anhydride, the added amount of the antioxidant is 0.01-5%, preferably 0.05-2%, and more preferably 0.1-1%.

[0045] Wherein, the antioxidant is selected from one or more of phenolic antioxidants, aromatic amine antioxidants and heterocyclic antioxidants.

[0046] The phenolic antioxidant is selected from 4,4'-isopropylidene bisphenol (bisphenol A), 2,2'-bis-(3-methyl-4-hydroxyphenyl) propane (bisphenol C), 4,4'-dihydroxybiphenyl (antioxidant DOD), 4,4-dihydroxy-3,3',5,5'-tetra-tert-butylbiphenyl (antioxidant 712), 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol) (antioxidant 2246), 4,4'-methylene-bis-(2-methyl-6-tert-butylphenol) (antioxidant methylene 736), 2,2'-methylene-bis-(4-ethyl-6-tert-butylphenol) (antioxidant 425), 2,2'-methylene-bis-(4-methyl-6-cyclohexylphenol) (antioxidant ZKF), 2,2'-methylene-bis[4-methyl-6-(α-methylcyclohexyl) Phenol] (antioxidant WSP), 2,2'-methylene-bis-(6-α-methylbenzyl-p-cresol), 4,4'-methylene-bis-(2,6-di-tert-butylphenol) (antioxidant T511), 4,4'-methylene-bis-(2-tert-butylphenol) (antioxidant 702), 2,2'-ethylene-bis-(4-methyl-6-tert-butylphenol), 4,4'-ethylene-bis-(2-methyl-6-tert-butylphenol), 4,4'-ethylene-bis-(2,6-di-tert-butylphenol), 4,4'-ethylene-bis-(6-tert-butyl-m-cresol) (antioxidant BBM), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (antioxidant TCA) and 4,4'-isobutylene-bis-(2,6-di-tert-butylphenol).

[0047] The antioxidant can also be one or more of N,N'-hexamethylene bis-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide) (antioxidant 1098), hexanediol bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (antioxidant 259), bis-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl) hydrazine (antioxidant BPP), 2,2'-thioethylene glycol bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (antioxidant 1035) and triethylene glycol bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate (antioxidant 245).

[0048] The tert-butyl phenolic antioxidant is one or more of hydroquinone (TBHQ), gallic acid C1-C18 ester, 3-(3,5-di-tert-butyl-4-hydroxyphenyl) acrylate, antioxidant 1010, antioxidant 2246, antioxidant 1076 and antioxidant 300. The phenolic antioxidant can be specifically divided into bisphenol antioxidants and polyphenol antioxidants.

[0049] The bisphenol-type antioxidant is preferably a bisphenol composed of two monophenols having at least one tert-butyl group at the ortho position of the phenolic hydroxyl group connected by a methylene group, such as one or more of the following substances: 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol) (antioxidant 2246); 4,4'-methylene-bis-(2-methyl-6-tert-butylphenol) (antioxidant methylene 736); 4,4'-methylene-bis-(2,6-di-tert-butylphenol) (antioxidant T511); 4,4'-methylene-bis-(2-tert-butylphenol) (antioxidant 702).

[0050] Polyphenol antioxidants refer to phenols containing at least two phenolic hydroxyl groups on the same benzene ring in the same phenol antioxidant molecule, such as one or more of the following substances: tert-butylhydroquinone, di-tert-butylhydroquinone, pyrogallic acid, gallic acid C1-C18 esters, such as methyl gallate, ethyl gallate, propyl gallate, butyl gallate, pentyl gallate, hexyl gallate, heptyl gallate, octyl gallate, nonyl gallate, decyl gallate, dodecyl gallate, tetradecyl gallate, hexadecyl gallate, octadecyl gallate, octadecyl gallate, octadecyl gallate, etc. Specifically, polyphenol antioxidants are preferably tert-butylhydroquinone (TBHQ) and gallic acid C1-C18 esters, especially propyl gallate (PG), which have excellent antioxidant capacity.

[0051] The aromatic amine antioxidant is selected from N-phenyl-N'-cyclohexyl p-phenylenediamine (antioxidant 4010), N,N-(1,3-dimethylbutyl)-N'-phenyl p-phenylenediamine (antioxidant 4020), N,N'-bis-(1,4-dimethylpentyl) p-phenylenediamine (antioxidant 4030), N-p-tolyl-N'-(1,3-dimethylbutyl) p-phenylenediamine (antioxidant 4040), N,N'-diheptyl p-phenylenediamine (antioxidant 7 88), N-isopropyl-N'-phenyl-p-phenylenediamine (antioxidant 4010NA), N-isopropyl-N'-p-methylphenyl-p-phenylenediamine (antioxidant methyl 4010NA), N,N'-dimethylphenyl-p-phenylenediamine (antioxidant PPD-A), N,N'-diphenyl-p-phenylenediamine (antioxidant H), N,N'-di-(β-naphthyl)-p-phenylenediamine (antioxidant DNP), N,N'-di-sec-butyl-p-phenylenediamine (antioxidant U-5, antioxidant agent 44PD), N,N'-dioctyl p-phenylenediamine (antioxidant 88), N,N'-bis-(1-methylheptyl) p-phenylenediamine (antioxidant 288), N,N'-bis-(1-ethyl-3-methylpentyl) p-phenylenediamine (antioxidant 8L), N,N'-bis-(1,4-dimethylbutyl) p-phenylenediamine (antioxidant 66), N-octyl-N'-phenyl p-phenylenediamine (antioxidant 688), N-isobutyl-N'-phenyl p-phenylenediamine One or more of amine (antioxidant 5L), N,N'-dimethyl-N,N'-bis-(1-methylpropyl)-p-phenylenediamine (antioxidant 32), N-(p-tolylsulfonyl)-N'-phenyl-p-phenylenediamine (antioxidant TPPD), N-(3-methacryloyloxy-2-hydroxypropyl)-N'-phenyl-p-phenylenediamine (antioxidant G-1), N-(3-anilinophenyl) methacrylamide and N-hexyl-N'-phenyl-p-phenylenediamine. The hydrocarbon-substituted p-phenylenediamine antioxidant is preferably a dialkyl p-phenylenediamine, and particularly preferably a dialkyl p-phenylenediamine having an alkyl carbon atom number between 4 and 10, such as one or more of N,N'-diheptyl p-phenylenediamine, N,N'-di-sec-butyl p-phenylenediamine, N,N'-dioctyl p-phenylenediamine and N,N'-bis-(1-methylheptyl) p-phenylenediamine, and can also be one or more of N',N-diphenyl p-phenylenediamine, N,N'-hexamethylene-bis-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide, phenothiazine, antioxidant DNP, antioxidant H and antioxidant 4010.

[0052] The heterocyclic antioxidant is selected from one or more of benzotriazole, alkyl-substituted imidazoline, 2-mercaptobenzothiazole, 2,5-dimercapto-1,3,4-thiadiazole and derivatives thereof.

[0053] In order to remove the unreacted substrate and impurities in the product obtained by the addition reaction, the product of the addition reaction can be subjected to molecular distillation. Wherein, the molecular distillation includes a one-step molecular distillation; the cut point of the one-step molecular distillation is any temperature between 30-500°C, preferably any temperature between 50-300°C, and more preferably any temperature between 80-250°C; the pressure during the one-step molecular distillation is 0.05-50Pa, preferably 0.1-20Pa. The light components of the one-step molecular distillation are the unreacted substrate and impurities, and the heavy components are the final product. The light components of the one-step molecular distillation can be reused as the raw material for the addition reaction in step (1).

[0054] Wherein, the molecular distillation includes continuous primary molecular distillation and secondary molecular distillation; the cutting point of the primary molecular distillation is any temperature between 30-300°C, preferably any temperature between 50-250°C; the pressure of the primary molecular distillation is 0.05-50Pa, preferably 0.1-20Pa; the cutting point of the secondary molecular distillation is any temperature between 50-500°C, preferably any temperature between 100-300°C; the pressure of the secondary molecular distillation is 0.01-30Pa, preferably 0.1-20Pa. The primary molecular distillation removes unreacted substrates and impurities, and the remaining part continues to undergo secondary molecular distillation. The light component of the secondary molecular distillation is oleic acid methyl ester succinic acid monoester, and the heavy component is a fatty acid ester dimer cross-linked product. The light component of the primary molecular distillation and the heavy component of the secondary molecular distillation can be reused as raw materials for the addition reaction in step (1).

[0055] When the primary molecular distillation and the secondary molecular distillation are combined, the heavy components can be separated by the primary molecular distillation first, and then the light components can be subjected to secondary molecular distillation to separate the unreacted substrate and impurities. The above-mentioned heavy components include residual catalyst and methyl oleate succinic anhydride or methyl oleate succinic acid.

[0056] Wherein, the content of methyl oleyl succinic anhydride in the refined methyl oleyl succinic anhydride is 90-99.9wt%, preferably 95-99.9wt%.

[0057] In some embodiments of the present invention, the content of methyl oleyl succinic anhydride in the refined methyl oleyl succinic anhydride can be specifically 95.5wt%, 97.5wt%, 98wt%, 98.5wt%, 99wt%, 99.9wt% or any value in between the aforementioned ranges.

[0058] In some embodiments of the present invention, the refined methyl oleate succinic anhydride contains 0.1-2.5wt% of saturated fatty acid ester succinic anhydride. Specifically, the content of saturated fatty acid ester succinic anhydride can be 0.1wt%, 0.3wt%, 0.5wt%, 0.7wt%, 0.9wt%, 1.1wt%, 1.3wt%, 1.5wt%, 1.7wt%, 1.9wt%, 2.1wt%, 2.3wt%, 2.5wt% or any value between the aforementioned ranges.

[0059] A second aspect of the present invention provides a method for preparing a diesel additive, the method comprising:

[0060] The above-mentioned preparation method is used to prepare refined methyl oleate succinic anhydride;

[0061] Then, the refined oleyl methyl succinic anhydride is subjected to an esterification reaction with a hydroxyl-containing compound to obtain an esterification product; the content of oleyl methyl succinic acid monoester in the esterification product is 90-100wt%, preferably 92-100wt%. In the present invention, since the refined oleyl methyl succinic anhydride is used for the esterification reaction, the yield of oleyl methyl succinic acid monoester is high, and the esterification product can be directly used as a diesel additive without subsequent treatment such as purification.

[0062] The conditions of the esterification reaction include: a temperature of 40-180°C, preferably 50-120°C; a reaction time of 10 min-8 h, preferably 0.5-2 h; and a molar ratio of the methyl oleate succinic anhydride to the hydroxyl-containing compound of 1:(0.5-1.2), preferably 1:(0.8-1.1).

[0063] The hydroxyl-containing compound is selected from one or more of aliphatic alcohols, alicyclic alcohols, aromatic alcohols, phenols and alcohol ethers having 1-30 carbon atoms, preferably one or more of aliphatic alcohols, alicyclic alcohols, aromatic alcohols, phenols and alcohol ethers having 1-18 carbon atoms.

[0064] When the hydroxyl-containing compound is a fatty alcohol, it is C1-C 30 The chain fatty alcohol is preferably C1-C 18 The fatty alcohol is preferably a monohydric alcohol, and may be a primary alcohol, a secondary alcohol or a tertiary alcohol, and may also be a saturated or unsaturated, normal or isomeric fatty alcohol.

[0065] In some embodiments of the present invention, the saturated fatty alcohol can be methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, various isomeric pentanols, n-hexanol, various isomeric hexanols, n-heptanol, various isomeric heptanols, n-octanol, various isomeric octanols (such as 2-ethylhexanol), n-nonanol, various isomeric nonanols (such as 3,5,5-trimethylhexanol, 7-methyl-1-octanol), n-decanol, various isomeric decanols (such as 2-propylheptanol, 8-methyl-1-nonanol), various isomeric undecanols, lauryl alcohol, n-tridecanol, various isomeric tridecanols, n-tetradecanol, n-hexadecanol or n-octadecyl alcohol.

[0066] In some embodiments of the present invention, the unsaturated fatty alcohol can be propenol, 3-butene-1-ol, isopentenol, 3-hexene-1-ol, 1-heptene-3-ol, methylheptenol, 3-nonene-1-ol, 2,4-decadien-1-ol or oleyl alcohol.

[0067] The hydroxyl-containing compound may be C3-C 30 The alicyclic alcohol is preferably C4-C 18 The alicyclic alcohol is selected from one or more of cyclobutanol, cyclopentanol, cyclohexanol, 3-cyclopentene-1-ol, 2-cyclohexenol and 3-cyclohexene-1-methanol.

[0068] The hydroxyl-containing compound may be C6-C 30 Aromatic alcohol or phenol, preferably C6-C 30 Aromatic alcohol or phenol. The aromatic alcohol is selected from one or more of benzyl alcohol, phenylethyl alcohol and phenylpropanol; the phenol is selected from one or more of propylphenol, butylphenol, pentylphenol, heptylphenol, octylphenol, nonylphenol, decylphenol and dodecylphenol.

[0069] In a preferred embodiment of the present invention, the hydroxyl-containing compound can be methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, cyclohexanol, 3-cyclohexene-1-methanol, benzyl alcohol, n-octanol, isooctyl alcohol (such as 2-ethylhexanol), isononyl alcohol (such as 3,5,5-trimethylhexanol, 7-methyl-1-octanol), n-decanol, isodecyl alcohol (such as 2-propylheptanol, 8-methyl-1-nonanol), lauryl alcohol, oleyl alcohol and nonylphenol, as well as various structures of isomeric alcohols prepared by polymerization of ethylene, propylene or butene, such as isomeric nonanols, isomeric undecyl alcohols and isomeric tridecanols.

[0070] The structural formula of the alcohol ether described in the present invention is R 2 [OR 1 ] n OH, where R 1 is selected from -CH2CH2-, -CH(CH3)CH2-, -CH2CH(CH3)-; n is selected from an integer of 1-10; R 2Selected from substituted or unsubstituted C1-C 18 of hydrocarbon groups.

[0071] In some embodiments of the present invention, the alcohol ether is preferably selected from C3-C 18 The alcohol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol monotert-butyl ether, ethylene glycol monopentyl ether, ethylene glycol monohexyl ether, ethylene glycol monoheptyl ether, ethylene glycol monooctyl ether, ethylene glycol monoisooctyl ether, ethylene glycol monononyl ether, ethylene glycol monoisononyl ether, ethylene glycol monodecyl ether, ethylene glycol monoisoundecyl ether, ethylene glycol monolauryl ether, ethylene glycol monoisotridecyl ether, ethylene glycol monobenzyl ether, ethylene glycol monononylphenol ether, ethylene glycol monododecylphenol ether, ethylene glycol monooleyl alcohol ether, propylene glycol mono Propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monoisobutyl ether, propylene glycol monotert-butyl ether, propylene glycol monopentyl ether, propylene glycol monohexyl ether, propylene glycol monoheptyl ether, propylene glycol monooctyl ether, propylene glycol monoisooctyl ether, propylene glycol monononyl ether, propylene glycol monoisononyl ether, propylene glycol monodecyl ether, propylene glycol monoisoundecyl ether, propylene glycol monolauryl ether, propylene glycol monoisotridecyl ether, propylene glycol monobenzyl ether, propylene glycol monononylphenol ether, propylene glycol monododecylphenol ether, propylene glycol monooleyl alcohol ether, diethylene glycol monomethyl ether, diethylene glycol monoisooctyl ether, Diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monotert-butyl ether, diethylene glycol monopentyl ether, diethylene glycol monohexyl ether, diethylene glycol monooctyl ether, diethylene glycol monoisooctyl ether, diethylene glycol monononyl ether, diethylene glycol monoisononyl ether, diethylene glycol monodecyl ether, diethylene glycol monoisoundecyl ether, diethylene glycol monolauryl ether, diethylene glycol monoisotridecyl ether, diethylene glycol monobenzyl ether, diethylene glycol monononylphenol ether, diethylene glycol monododecylphenol ether, diethylene glycol monooleyl alcohol ether, dipropylene glycol mono Methyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monoisobutyl ether, dipropylene glycol monotert-butyl ether, dipropylene glycol monopentyl ether, dipropylene glycol monohexyl ether, dipropylene glycol monooctyl ether, dipropylene glycol monoisooctyl ether, dipropylene glycol monononyl ether, dipropylene glycol monoisononyl ether, dipropylene glycol monodecyl ether, dipropylene glycol monoisoundecyl ether, dipropylene glycol monolauryl ether, dipropylene glycol monoisotridecyl ether, dipropylene glycol monobenzyl ether, dipropylene glycol monononylphenol ether, dipropylene glycol monododecylphenol ether and dipropylene glycol monooleyl alcohol ether.

[0072] In a preferred embodiment of the present invention, the alcohol ether is selected from C3-C6 alcohol ethers, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, etc., diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether and diethylene glycol monotert-butyl ether.

[0073] In the present invention, a catalyst is also added during the esterification reaction; the catalyst is selected from one or more of aluminum chloride, sulfuric acid, hydrochloric acid, boron trifluoride, solid superacid, cation exchange resin and heteropolyacid. Adding a catalyst during the esterification reaction can accelerate the reaction rate, but it will also cause side reactions, so it is preferably not to use a catalyst.

[0074] In the present invention, an inhibitor is further added during the esterification reaction; the inhibitor is selected from one or more of triethylamine and pyridine.

[0075] In the present invention, a reaction solvent is further added to the addition reaction and the esterification reaction; the reaction solvent is selected from one or more of toluene, xylene and ethylbenzene. The reaction solvent added during the esterification reaction can be used as a water-carrying agent to promote the forward reaction. However, the reaction solvent is difficult to remove effectively. Therefore, the water generated by the reaction can be removed by continuously introducing an inert gas to avoid the use of a water-carrying agent.

[0076] The third aspect of the present invention provides a diesel additive prepared according to the second aspect of the present invention.

[0077] The fourth aspect of the present invention provides a method for preparing a diesel product, the method comprising: mixing a diesel base oil with an anti-wear agent; the anti-wear agent is the diesel additive provided by the third aspect of the present invention; the diesel additive is added to the diesel base oil in an amount of 50-400 μg / g.

[0078] The present invention is further described in detail by way of examples. The raw materials used in the examples can be obtained through commercial sources.

[0079] Among them, methyl oleate (content 85%) used in the embodiments and comparative examples was produced by Shanghai Aladdin Biochemical Technology Co., Ltd., anhydrous methanol (content 99.5%) and ethylene glycol monomethyl ether (content 99.7%) were produced by Sinopharm Chemical Reagent Company, maleic anhydride (content 99.5%) was produced by Beijing Inokai Technology Co., Ltd., and antioxidant 2246 (industrial grade) was produced by Nanjing Ruiyan Chemical Plant.

[0080] The molecular distillation device used in the embodiment is a VKL70-5FDRR full-heating full-gear pump molecular distillation evaporator produced by VTA Company of Germany.

[0081] Example 1

[0082] In this embodiment, methyl oleate and maleic anhydride are used as initial substrates to prepare methyl oleate succinate, which specifically includes the following steps:

[0083] (1) Addition reaction: Prepare a 3L reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, weigh 1500g of methyl oleate (mass fraction is 85%) and 745g of maleic anhydride (the molar ratio of methyl oleate to maleic anhydride is about 1:1.5) and place them in the above reactor, then add 6.7g of antioxidant 2246 (the amount of antioxidant 2246 is 0.3wt% of the total mass of the reactants) into the reactor, pass nitrogen for 5-10 minutes, then heat and stir under nitrogen protection to raise the temperature to 210°C, reflux for 6 hours, and collect the resulting reaction product. The mass of the reaction product is 2186.3g.

[0084] (2) Molecular distillation: Take 1000g of the reaction product prepared in step (1), and perform a first-stage molecular distillation using a molecular distillation apparatus, the cut point temperature of the first-stage molecular distillation is 146°C, and the absolute pressure is 2.0Pa. Perform a second-stage molecular distillation on the heavy components obtained by the first-stage molecular distillation, the cut point temperature of the second-stage molecular distillation is 285°C, and the absolute pressure is 0.5Pa. Collect the light components of the second-stage molecular distillation as refined methyl oleate succinic anhydride. The mass of the refined methyl oleate succinic anhydride obtained is 573g. Figure 1 It can be seen that the content of methyl oleyl succinic anhydride (ASA) in the obtained refined methyl oleyl succinic anhydride product is 94.7 wt %.

[0085] (3) Esterification reaction: 500 g of refined methyl oleyl succinic anhydride was placed in a 1000 mL reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, 32.5 g of methanol was added (the molar ratio of methyl oleyl succinic anhydride to methanol was 1:0.8), nitrogen was introduced into the reactor for 5-10 minutes, the reaction was stirred at 60° C. for 0.5 hour, and then cooled to room temperature to obtain a methyl oleyl succinic acid monomethyl ester product containing the following structural formula 1 and / or structural formula 2, with a purity of 94.0 wt %.

[0086]

[0087] from Figure 5 It can be seen that the purity of methyl oleyl succinic acid monomethyl ester in the product of the reaction of methyl oleyl succinic anhydride and methanol refined by molecular distillation is relatively high (mass fraction is 94wt%), and other impurities are methyl oleate and saturated fatty acid-based methyl succinate.

[0088] Example 2

[0089] In this embodiment, biodiesel (the content of unsaturated fatty acid methyl ester in biodiesel exceeds 90wt%, and the composition of fatty acid methyl ester is shown in Table 1) and maleic anhydride are used as initial substrates to prepare methyl oleate succinate, which specifically includes the following steps:

[0090] (1) Addition reaction: a 3L reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube was prepared, 1500g of biodiesel and 991.5g of maleic anhydride were weighed and placed in the reactor (since the main component of biodiesel is methyl oleate, for the convenience of calculation, the relative molecular mass of methyl oleate was used as the relative molecular mass of biodiesel, that is, the relative molecular mass was 298.49g / mol, and the molar ratio of unsaturated fatty acid methyl ester to maleic anhydride was calculated to be about 1:2), and then 2.5g of antioxidant 2246 was added to the reactor (the amount of antioxidant was 0.1wt% of the total mass of the reactants), and nitrogen was introduced. Then, the temperature was raised to 250°C under nitrogen protection by heating and stirring, and reflux reaction was carried out for 5 hours, and the excess maleic anhydride was removed by reduced pressure distillation to obtain an addition reaction product.

[0091] Table 1 Composition of fatty acid methyl esters in biodiesel

[0092] Fatty acid methyl esters Mass fraction (wt%) Methyl myristate (C14:0) 0.2 Methyl palmitate (C16:0) 2.3 Methyl Palmitoleate (C16:1) 0.5 Methyl stearate (C18:0) 0.7 Methyl oleate (C18:1) 78.6 Methyl Linoleate (C18:2) 13.8 Methyl linolenate (C18:3) 1.6 Arachidic acid methyl ester (C20:0) 0.1 Arachidate Methyl Ester (C20:1) 0.1 Total methyl esters 97.9

[0093] (2) Molecular distillation: 1000 g of the reaction product prepared in step (1) was taken and subjected to primary molecular distillation using a molecular distillation apparatus, the cut point temperature of the primary molecular distillation being 146° C. and the absolute pressure being 2.0 Pa, the heavy components obtained by the primary molecular distillation were subjected to secondary molecular distillation, the cut point temperature of the secondary molecular distillation being 285° C. and the absolute pressure being 0.5 Pa, and the light components of the secondary molecular distillation were collected as refined methyl oleate succinic anhydride. The mass of the obtained refined methyl oleate succinic anhydride was 523 g.

[0094] (3) Esterification reaction: 500 g of refined methyl oleyl succinic anhydride was placed in a 1 L reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, 32.5 g of methanol was added (the molar ratio of methyl oleyl succinic anhydride to methanol was 1:0.8), nitrogen was introduced into the reactor for 5-10 minutes, the reaction was stirred at 60° C. for 0.5 hour, and then cooled to room temperature to obtain methyl oleyl succinic acid monomethyl ester product with a purity of 92.4 wt %.

[0095] Example 3

[0096] In this example, methyl oleate (mass fraction of 85%) and maleic anhydride are used as initial substrates to prepare methyl oleate succinic acid monoethylene glycol monomethyl ether ester. The preparation method is carried out with reference to Example 1. The difference from Example 1 is that:

[0097] (3) Esterification reaction: 200 g of refined methyl oleyl succinic anhydride was placed in a 500 mL reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, 38.4 g of ethylene glycol monomethyl ether (the molar ratio of methyl oleyl succinic anhydride to ethylene glycol monomethyl ether was 1:1) was added, nitrogen was introduced into the reactor for 5-10 minutes, the mixture was stirred at 60° C. for 1 hour, and then cooled to room temperature and allowed to stand for 24 hours to obtain methyl oleyl succinic acid monoethylene glycol monomethyl ether product with a purity of 95.8 wt %.

[0098] Example 4

[0099] The method for preparing methyl oleate succinic anhydride in this embodiment is the same as that in embodiment 1, except that:

[0100] (1) Addition reaction: A 1L reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube was prepared, 500g of methyl oleate (mass fraction of 85%) and 249g of maleic anhydride (the molar ratio of methyl oleate to maleic anhydride was about 1:1.5) were weighed and placed in the above reactor, and then 7.49g of tert-butyl hydroquinone (TBHQ) (the amount of tert-butyl hydroquinone was 1.0wt% of the total mass of the reactants) was added to the reactor, nitrogen was introduced for 5-10 minutes, and then heated and stirred under nitrogen protection to 210°C, refluxed for 6 hours, and the resulting reaction product was collected. The mass of the reaction product was 730g.

[0101] (2) Molecular distillation: 500 g of the reaction product prepared in step (1) was taken and subjected to primary molecular distillation using a molecular distillation apparatus, the cut point temperature of the primary molecular distillation being 146° C. and the absolute pressure being 2.0 Pa, the heavy components obtained by the primary molecular distillation were subjected to secondary molecular distillation, the cut point temperature of the secondary molecular distillation being 285° C. and the absolute pressure being 0.5 Pa, and the light components of the secondary molecular distillation were collected as refined methyl oleate succinic anhydride. The mass of the obtained refined methyl oleate succinic anhydride was 573 g. The content of methyl oleate succinic anhydride (ASA) in the obtained refined methyl oleate succinic anhydride product was 97.0 wt%.

[0102] Example 5

[0103] This example prepares methyl oleate succinic anhydride by referring to the method of Example 1, except that:

[0104] (1) Addition reaction: Prepare a 1L reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, weigh 500g of methyl oleate (mass fraction is 85%) and 249g of maleic anhydride (the molar ratio of methyl oleate to maleic anhydride is about 1:1.5) and place them in the above reactor, then add 3.7g of propyl gallate (PG) to the reactor (the amount of propyl gallate is 0.5wt% of the total mass of the reactants), pass nitrogen for 5-10 minutes, then heat and stir under nitrogen protection to raise the temperature to 210°C, reflux for 6 hours, and collect the resulting reaction product. The mass of the reaction product is 740g.

[0105] (2) Molecular distillation: 500 g of the reaction product prepared in step (1) was taken and subjected to primary molecular distillation using a molecular distillation apparatus, the cut point temperature of the primary molecular distillation being 146° C. and the absolute pressure being 2.0 Pa, the heavy components obtained by the primary molecular distillation were subjected to secondary molecular distillation, the cut point temperature of the secondary molecular distillation being 285° C. and the absolute pressure being 0.5 Pa, and the light components of the secondary molecular distillation were collected as refined methyl oleate succinic anhydride. The mass of the obtained refined methyl oleate succinic anhydride was 573 g. The content of methyl oleate succinic anhydride (ASA) in the obtained refined methyl oleate succinic anhydride product was 98.2 wt %.

[0106] Example 6

[0107] This example prepares methyl oleate succinic anhydride by referring to the method of Example 5, except that:

[0108] (2) Molecular distillation: 500 g of the reaction product prepared in step (1) was taken and subjected to primary molecular distillation using a molecular distillation apparatus. The cut point temperature of the primary molecular distillation was 146° C. and the absolute pressure was 2.0 Pa. The heavy components of the primary molecular distillation were collected as refined methyl oleate succinic anhydride. The mass of the obtained refined methyl oleate succinic anhydride was 573 g. The content of methyl oleate succinic anhydride (ASA) in the obtained refined methyl oleate succinic anhydride product was 96.5 wt %.

[0109] According to the content of methyl oleate succinic anhydride in the refined methyl oleate succinic anhydride products obtained in Examples 1-2 and Examples 4-6, the addition of antioxidants such as antioxidant 2246, tert-butylhydroquinone and propyl gallate during the addition reaction of methyl oleate and maleic anhydride is beneficial to increasing the content of methyl oleate succinic anhydride in the product. In particular, when propyl gallate is used as an antioxidant, the yield of methyl oleate succinic anhydride is high, and the refined methyl oleate succinic anhydride obtained by molecular distillation has a higher purity. The content of methyl oleate succinic anhydride in the first-stage molecular distillation product can reach 96.5wt%, and the content of methyl oleate succinic anhydride in the second-stage molecular distillation product can reach 98.2wt%, thereby improving the product yield.

[0110] Comparative Example 1

[0111] This comparative example uses methyl oleate and maleic anhydride as initial substrates to prepare methyl oleate succinate monomethyl ester, which specifically includes the following steps:

[0112] (1) Addition reaction: Weigh 1500 g of methyl oleate (mass fraction 85%) and 745 g of maleic anhydride (the molar ratio of methyl oleate to maleic anhydride is about 1:1.5) and place them in a 3 L reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, introduce nitrogen for 5-10 minutes, heat and stir to raise the temperature to 210°C, reflux for 6 hours, and collect the resulting reaction product. Figure 2 It can be seen that the content of methyl oleyl succinic anhydride (ASA) in the obtained reaction product is 34 wt %.

[0113] (2) Esterification reaction: 500 g of the reaction product of step (1) was placed in a 1000 mL reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, 32.5 g of methanol (the molar ratio of methyl oleate succinic anhydride to methanol was 1:0.8), nitrogen was introduced into the reactor for 5-10 minutes, the reaction was stirred at 60° C. for 0.5 hour, and then cooled to room temperature to obtain methyl oleate succinic acid monomethyl ester product with a mass fraction of 43.1 wt%. Figure 6 It can be seen that the final product obtained contains a large amount of unreacted methyl oleate in addition to the target product.

[0114] Comparative Example 2

[0115] In this comparative example, biodiesel (the content of unsaturated fatty acid methyl ester in biodiesel exceeds 90%, and the composition of fatty acid methyl ester is shown in Table 1) and maleic anhydride are used as initial substrates to prepare methyl oleate succinate, which specifically includes the following steps:

[0116] (1) Addition reaction: A 3 L reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube was prepared, 1500 g of biodiesel (the fatty acid methyl ester composition in biodiesel is shown in Table 1) and 991.5 g of maleic anhydride were weighed and placed in the reactor, heated and stirred to 250° C., refluxed for 5 hours, and the excess maleic anhydride was removed by vacuum distillation to obtain an addition reaction product. The content of oleyl methyl succinic anhydride (ASA) in the obtained reaction product was 29 wt %.

[0117] (2) Esterification reaction: 500 g of the addition reaction product of step (1) was placed in a 1000 mL reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, 32.5 g of methanol (the molar ratio of methyl oleate succinic anhydride to methanol was 1:0.8) was added, nitrogen was introduced into the reactor for 5-10 minutes, the reaction was stirred at 60° C. for 0.5 hour, and then cooled to room temperature to obtain methyl oleate succinic acid monomethyl ester product with a purity of 37.8 wt %.

[0118] Comparative Example 3

[0119] In this comparative example, methyl oleate (mass fraction of 85%) and maleic anhydride are used as initial substrates to prepare methyl oleate succinic acid monoethylene glycol monomethyl ether ester. The preparation method is carried out with reference to comparative example 1. The difference from comparative example 1 is that:

[0120] (2) Esterification reaction: 200 g of the reaction product of step (1) of comparative example 1 was weighed and placed in a 500 mL reactor equipped with an electric stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, 38.4 g of ethylene glycol monomethyl ether (the molar ratio of methyl oleate succinic anhydride to ethylene glycol monomethyl ether was 1:1) was added, nitrogen was introduced into the reactor for 5-10 minutes, the reaction was stirred at 60° C. for 1 hour, then cooled to room temperature and allowed to stand for 24 hours to obtain methyl oleate succinic acid monoethylene glycol monomethyl ether product with a purity of 42.3 wt %.

[0121] Comparing the yields of the products obtained in the examples and comparative examples, it can be seen that when the reaction intermediate of oleyl methyl succinic anhydride obtained by the addition reaction is subjected to molecular distillation and refining before being put into the esterification reaction, the yield of the obtained oleyl methyl succinic acid monoester can reach more than 90%, while when the addition reaction product that has not been subjected to molecular distillation and refining is directly used as a substrate for the esterification reaction, the yield of the obtained oleyl methyl succinic acid monoester is only about 40%. It can be seen that purifying the reaction intermediate of unsaturated fatty acid ester and maleic anhydride can greatly improve the yield of oleyl methyl succinic acid monoester.

[0122] Lubricity test

[0123] Test method: The lubricity of diesel is measured by the wear scar diameter (WSD) at 60°C on a high-frequency reciprocating rig (HFRR) (produced by PCS Instruments, UK) according to the method described in CEC-F-06-A-96 or ISO / FDIS12156-1 (ASTM D6079 in the United States). The report result WS1.4 is obtained by correcting the effects of temperature and humidity. At present, most diesel standards in the world, such as the European standard EN590 and the Chinese automotive diesel standard GB / T 19147, use a wear scar diameter of less than 460μm (60°C) as the basis for the qualified standard of diesel lubricity.

[0124] The sulfur contents of low-sulfur diesel A and low-sulfur diesel B used for lubrication performance testing were 6 mg kg -1 and 11 mg kg -1 , the wear spot diameters are 640μm and 545μm respectively, and their specific properties are shown in Table 2.

[0125] Table 2 Physical and chemical properties of low sulfur diesel

[0126]

[0127]

[0128] The methyl oleate succinate prepared in Examples 1-3 and Comparative Examples 1-3 was added to low-sulfur diesel for lubrication performance testing. The test results and the HFRR method (ISO 12156-1) wear diameter WS1.4 of the diesel before and after addition are shown in Table 3, wherein the smaller the wear diameter, the better the lubricity of the diesel.

[0129] Table 3 Improvement of diesel lubricity by methyl oleate succinate products

[0130]

[0131]

[0132] As can be seen from Table 3, compared with the lubricity of the products obtained without molecular distillation in Comparative Examples 1-3 on diesel, the higher purity methyl oleyl succinic acid monomethyl ester prepared by the methods of Examples 1-3 of the present invention has a more obvious effect on improving the lubricity of low-sulfur diesel.

[0133] Corrosion test

[0134] The methyl oleyl succinate monoester prepared in Examples 1-3 and Comparative Examples 1-3 was added to low-sulfur diesel to test the corrosive effect of the oil sample, and the test method adopted GB / T 11143. The test results are shown in Table 4.

[0135] Table 4 Improvement of diesel corrosion performance by methyl oleate succinate products

[0136] Oil Sample <![CDATA[Added dose / mg·kg -1 > performance Blank Diesel A 0 100% corrosion within 4 hours Blank diesel A+Example 1 50 24 hours no corrosion Blank diesel A+Example 2 50 24 hours no corrosion Blank diesel A+Example 3 50 24 hours no corrosion Blank diesel A+Comparative Example 1 50 13% corrosion in 4 hours Blank diesel A+Comparative Example 2 50 20% corrosion within 4 hours Blank diesel A+Comparative Example 3 50 20% corrosion within 4 hours Blank Diesel B 0 100% corrosion within 4 hours Blank diesel B+Example 1 50 24 hours no corrosion Blank Diesel B+Example 2 50 24 hours no corrosion Blank Diesel B+Example 3 50 24 hours no corrosion Blank diesel B+Comparative Example 1 50 15% corrosion within 4 hours Blank diesel B+Comparative Example 2 50 20% corrosion within 4 hours Blank diesel B+Comparative Example 3 50 25% corrosion within 4 hours

[0137] Combination Fig. 9 As shown in Table 4, the addition of methyl oleyl succinic acid monoester with higher purity synthesized by the method of the present invention has a significant effect on improving the rust resistance of diesel, which is significantly better than the product without the molecular distillation step.

[0138] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0139] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0140] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing methyl oleate succinic anhydride, characterized in that: The method comprises the following steps: (1) reacting a substrate containing methyl oleate with maleic anhydride under addition reaction conditions to obtain a methyl oleate succinic anhydride reaction intermediate; (2) molecularly distilling the methyl oleate succinic anhydride reaction intermediate to obtain refined methyl oleate succinic anhydride.

2. The preparation method according to claim 1, wherein The methyl oleate-containing substrate is biodiesel or methyl oleate; the content of methyl oleate in the biodiesel is 30-100wt%, preferably 50-95wt%, and more preferably 60-90wt%; The conditions of the addition reaction include: reaction temperature of 100-280°C, preferably 180-240°C; reaction time of 1-20h, preferably 6-12h; The molar ratio of the substrate containing methyl oleate to maleic anhydride is 1:(0.1-10), preferably 1:(0.5-5); Preferably, an antioxidant is added in the reaction of step (1), and the amount of the antioxidant added is 0.01-5%, preferably 0.05-2%, and more preferably 0.1-1%, based on the total weight of the substrate containing methyl oleate and the maleic anhydride; Preferably, the antioxidant is selected from one or more of phenolic antioxidants, aromatic amine antioxidants and heterocyclic antioxidants; Further preferably, the phenolic antioxidant is selected from one or more of tert-butylhydroquinone, gallic acid C1-C18 ester, 3-(3,5-di-tert-butyl-4-hydroxyphenyl) acrylate, antioxidant 1010, antioxidant 2246, antioxidant 1076 and antioxidant 300; Further preferably, the aromatic amine antioxidant is selected from one or more of N',N-diphenyl-p-phenylenediamine, N,N'-hexamethylene-bis-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide, phenothiazine, antioxidant DNP, antioxidant H and antioxidant 4010; More preferably, the heterocyclic antioxidant is selected from one or more of benzotriazole, alkyl-substituted imidazoline, 2-mercaptobenzothiazole, 2,5-dimercapto-1,3,4-thiadiazole and derivatives thereof.

3. The preparation method according to claim 1, wherein The molecular distillation includes one-step molecular distillation; the cutting point of the one-step molecular distillation is any temperature between 30-500°C, preferably any temperature between 50-300°C, and further preferably any temperature between 80-250°C; the pressure during the one-step molecular distillation is 0.05-50Pa, preferably 0.1-20Pa.

4. The preparation method according to claim 1, wherein The molecular distillation includes continuous primary molecular distillation and secondary molecular distillation; The cutting point of the first-stage molecular distillation is any temperature between 30-300°C, preferably any temperature between 50-250°C; the pressure of the first-stage molecular distillation is 0.05-50Pa, preferably 0.1-20Pa; The cutting point of the secondary molecular distillation is any temperature between 50-500° C., preferably any temperature between 100-300° C.; the pressure of the secondary molecular distillation is 0.01-30 Pa, preferably 0.1-20 Pa.

5. The preparation method according to claim 1, wherein The molecular distillation comprises a one-step molecular distillation, and the light component of the one-step molecular distillation is returned to step (1) as a raw material for the addition reaction; or The molecular distillation comprises continuous primary molecular distillation and secondary molecular distillation, and the light components of the primary molecular distillation and / or the heavy components of the secondary molecular distillation are returned to step (1) as addition reaction raw materials.

6. The preparation method according to claim 1, wherein The content of methyl oleyl succinic anhydride in the refined methyl oleyl succinic anhydride is 90-99.9 wt %, preferably 95-99.9 wt %.

7. A method for preparing a diesel additive, characterized in that: The method includes: Refined methyl oleate succinic anhydride is prepared by the preparation method according to any one of claims 1 to 6; Then, the refined methyl oleyl succinic anhydride is subjected to an esterification reaction with a hydroxyl-containing compound to obtain an esterification product; the content of methyl oleyl succinic acid monoester in the esterification product is 90-100wt%, preferably 92-100wt%.

8. The preparation method according to claim 7, wherein: The conditions of the esterification reaction include: temperature of 40-180°C, preferably 50-120°C; reaction time of 10min-8h, preferably 0.5-2h; The molar ratio of the methyl oleyl succinic anhydride to the hydroxyl-containing compound is 1:(0.5-1.2), preferably 1:(0.8-1.1); Preferably, the hydroxyl-containing compound is selected from one or more of aliphatic alcohols, alicyclic alcohols, aromatic alcohols, phenols and alcohol ethers having 1 to 30 carbon atoms, preferably one or more of aliphatic alcohols, alicyclic alcohols, aromatic alcohols, phenols and alcohol ethers having 1 to 18 carbon atoms; Preferably, the fatty alcohol is a saturated or unsaturated, normal or isomeric fatty alcohol; Preferably, the alicyclic alcohol is selected from one or more of cyclobutanol, cyclopentanol, cyclohexanol, 3-cyclopentene-1-ol, 2-cyclohexenol and 3-cyclohexene-1-methanol; Preferably, the aromatic alcohol is selected from one or more of benzyl alcohol, phenylethyl alcohol and phenylpropanol; Preferably, the phenol is selected from one or more of propylphenol, butylphenol, pentylphenol, heptylphenol, octylphenol, nonylphenol, decylphenol and dodecylphenol; Preferably, the structural formula of the alcohol ether is R 2 [OR 1 ] n OH, where R 1 is selected from -CH2CH2-, -CH(CH3)CH2-, -CH2CH(CH3)-; n is selected from an integer of 1-10; R 2 Selected from substituted or unsubstituted C1-C 18 of hydrocarbon groups.

9. The diesel additive prepared according to the preparation method according to claim 7 or 8.

10. A method for preparing a diesel product, characterized in that: The method comprises: mixing diesel base oil with an anti-wear agent; the anti-wear agent is the diesel additive according to claim 9; and the diesel additive is added in an amount of 50-400 μg / g to the diesel base oil.

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