Imides and their preparation method and use

Abstract

The present invention provides an imide compound and a preparation method and use thereof. The imide compound of the present invention has a structure as shown in formula (I): wherein the definition of each group is as shown in the specification. The imide compound of the present invention has excellent anti-wear and anti-corrosion properties and can improve the lubricity and anti-corrosion properties of diesel.

Description

Technical Field

[0001] The invention relates to an imide compound, in particular to an imide compound which has good anti-wear performance and is suitable for being used as a diesel anti-wear agent. Background Art

[0002] As countries around the world pay more and more attention to environmental protection issues, reducing diesel exhaust pollution and producing high-quality clean diesel have become the development direction of the modern oil refining industry. This kind of diesel generally has the characteristics of low sulfur content, low aromatics, high cetane number, and light fraction. Studies have shown that sulfur is the most harmful element that increases CH, CO, and especially inhalable particulate matter (PM) in diesel engine emissions, so reducing the sulfur content in diesel is particularly important for improving air pollution. At present, the diesel specifications in the United States, Canada, and Western European countries stipulate that the sulfur content of diesel is less than 0.05%, and some countries have even stipulated that it is less than 0.0015%. Because they generally use more stringent hydrogenation processes, the content of polar oxygen-containing and nitrogen-containing compounds in diesel is very low, and the content of polycyclic and bicyclic aromatic light is also low, thereby reducing the natural lubrication performance of diesel, causing some injection pumps that rely on diesel for lubrication, such as rotary pumps and distribution pumps, to wear and reduce their service life.

[0003] The above problems can be alleviated by adding additives to diesel. It is generally believed that diesel anti-wear agents can make up for the loss of lubricating components in diesel caused by hydrogenation treatment, thereby improving the lubricity of diesel.

[0004] Monounsaturated fatty acid ester is a kind of oil derivative, which has the advantages of being natural, renewable, biodegradable and environmentally friendly. Monounsaturated fatty acid ester can be obtained by esterification of oleic acid with related alcohols or by transesterification of oleic acid methyl ester with corresponding alcohols. The use of natural plant monounsaturated fatty acid ester as a raw material source for chemical products has attracted more and more attention from countries around the world. The use of natural plant monounsaturated fatty acid ester to replace or partially replace petroleum in the production of chemical products has flourished in various fields.

[0005] US 4997456 discloses a hexadecene imide compound and an eicosanyl imide compound, which are added to gasoline or diesel to reduce or prevent the formation of deposits in a carburetor or injector of an internal combustion engine.

[0006] CN 106544063B discloses a hydroxyalkyl-substituted succinimide compound for reducing friction or wear in an engine and improving fuel economy.

[0007] WO 2012030524A2 discloses a compound obtained by reacting a maleic anhydride fatty acid with a polyol, a polyene polyamine, an alkanolamine and an alkylene oxide, which is used to improve the lubricity of hydrocarbon fuels and lubricating oils.

[0008] CN 106609167A and CN 107794096A disclose a diesel antiwear agent, one component of which is a hydrocarbon-substituted hydrazide compound obtained by reacting hydrocarbon-substituted succinic anhydride with hydrazine at 20-250° C., which is used to improve the lubricity of low-sulfur diesel and has an improving effect on the rust of diesel. Summary of the invention

[0009] The invention provides an imide compound and a preparation method and application thereof.

[0010] The imide compound of the present invention has a structure as shown in formula (I):

[0011]

[0012] In formula (I), the R1 group is selected from H, C1 to C 20 A straight or branched alkyl group, R2 group is C1~C 20 A straight or branched alkylene group, R3 group is selected from C5~C 24 A straight chain or branched alkyl group;

[0013] n is a positive integer between 1 and 10, and the A groups and A' groups in the n repeating units are each independently selected from -CH=CH-, -CH2-CH2-, and a single bond;

[0014] The G groups in the n repeating units are each independently selected from the group represented by formula (II);

[0015]

[0016] In formula (II), * represents the binding end bonded to formula (I);

[0017] The G' groups in formula (II) are each independently selected from the group represented by formula (III);

[0018]

[0019] In formula (III), * represents the binding end bonded to the nitrogen atom in formula (II);

[0020] m is an integer between 0 and 10, and the R4 groups in the m repeating units are each independently selected from C1 to C 20 The m T groups are independently selected from —NR”-, C 3～10 The nitrogen-containing heterocyclic group, wherein the R" groups are independently selected from H, C1-C6 straight chain or branched alkyl; R5 groups are selected from H, C1-C 20 A straight chain or branched alkyl group, a group represented by formula (IV);

[0021]

[0022] In formula (IV), the R1 group is selected from H, C1 to C 20 A straight or branched alkyl group, R2 group is C1~C 20 A straight or branched alkylene group, R3 group is selected from C5~C 24 A straight chain or branched alkyl group;

[0023] n' is a positive integer between 1 and 10, and the A group and the A' group in the n' repeating units are each independently selected from -CH=CH-, -CH2-CH2-, and a single bond;

[0024] The G" groups in the n'repeating units are independently selected from H, C1-C 20 A straight or branched alkyl group, a group represented by formula (V), in formula (IV), there is a G" group selected from the group represented by formula (V);

[0025]

[0026] In formula (V), * represents the bonding end bonded to formula (IV), and △ represents the bonding end bonded to formula (III).

[0027] According to the present invention, preferably, in formula (I), the R1 group is selected from H, C1 to C 10 A straight or branched alkyl group, R2 group is C1~C 10 A straight or branched alkylene group, R3 group is selected from C5~C 20 A straight or branched alkyl group; n is a positive integer between 1 and 5; in formula (III), m is a positive integer between 0 and 5, and the R4 groups in the m repeating units are each independently selected from C1 to C 10 The m T groups are independently selected from —NR”-, C 3～6 A nitrogen-containing heterocyclic group, wherein the R" groups are independently selected from H, C1-C4 straight chain or branched alkyl; in formula (IV), the R1 group is selected from H, C1-C 10 A straight or branched alkyl group, R2 group is C1~C 10 A straight or branched alkylene group, R3 group is selected from C5~C 20 A straight chain or branched alkyl group;

[0028] n' is a positive integer between 1 and 5; the G" groups in the n' repeating units are independently selected from H, C1~C 10 A straight chain or branched alkyl group, a group represented by formula (V).

[0029] According to the present invention, optionally, n can be 1, 2, 3, 4, 5; m can be 0, 1, 2, 3, 4, 5; and n' can be 1, 2, 3, 4, 5.

[0030] According to the present invention, optionally, the C 3～10 The nitrogen-containing heterocyclic group is a nitrogen-containing heterocyclic group obtained by removing two H from the nitrogen-containing heterocyclic compound represented by formula (VI);

[0031]

[0032] In formula (VI), R I The group is a C1-C9 straight chain or branched alkylene group, R II The group is a C1-C9 straight chain or branched alkylene group, R I Group and R II The sum of the carbon atoms of the group is an integer between 3 and 10; the D group is -O-, -S- or -NR"-, wherein the R" group is selected from H, a C1-C4 straight chain or branched alkyl group.

[0033] According to the present invention, examples of the nitrogen-containing heterocyclic compound represented by formula (VI) include one or more of the following compounds: 4-aminomorpholine, 3-methyl 4-aminomorpholine, 4-(2-aminomethyl)morpholine, 4-(2-aminoethyl)morpholine, 3-methyl-4-(2-aminoethyl)morpholine, N-(3-aminopropyl)morpholine, 4-morpholinebutylamine, 1,4-bis-(3-aminopropyl)piperazine, N-(3-aminopropyl)piperazine, 1,4-piperazinediethylamine, 1-( 2-aminoethyl)piperazine, 2-methyl-1-(2-aminoethyl)piperazine, 1,4-piperazinedimethylamine, piperazine-1-methylamine, 1,4-diaminopiperazine, 2-methyl-1,4-piperazinediamine, 2-(2-methylpiperazin-1-yl)-1-ethylamine, 2-methyl-2-(4-morpholino)propylamine, 2-(2-methylmorpholin-4-yl)ethane-1-amine, thiomorpholine-4-methylamine, 4-(2-aminoethyl)thiomorpholine, 4-(3-aminopropyl)thiomorpholine.

[0034] According to the present invention, the C 3～10 Examples of the nitrogen-containing heterocyclic group include the following groups:

[0035]

[0036] According to the present invention, the C 3～10 The nitrogen-containing heterocyclic group is preferably C 3～6 The nitrogen-containing heterocyclic group is a nitrogen-containing heterocyclic group obtained by removing two H from the nitrogen-containing heterocyclic compound represented by formula (VII);

[0037]

[0038] In formula (VII), R I The group is a C1-C5 straight chain or branched alkylene group, R II The group is a C1-C5 straight chain or branched alkylene group, R I Group and R II The sum of the carbon atoms of the group is an integer between 3 and 6; the D group is -O-, -S- or -NR"-, wherein the R" group is selected from H, a C1-C4 straight chain or branched alkyl group.

[0039] According to the present invention, the imide compound is a compound of the following types or a composition obtained by combining them in any proportion:

[0040] and / or

[0041]

[0042] According to the present invention, the imide compound is any one of the following single compounds or a composition obtained by combining the single compounds in any proportion:

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] The method for preparing the imide compound of the present invention comprises:

[0049] (1) a step of reacting maleic anhydride with a compound represented by formula (X);

[0050]

[0051] In formula (X), the R1' group is selected from H, C1-C 20 A straight or branched alkyl group, R2' group is C1~C 20 A straight or branched alkylene group, R3' group is selected from C5~C 24 A straight chain or branched alkyl group;

[0052] n" is a positive integer between 1 and 10, the A groups and A' groups in the n" repeating units are each independently selected from -CH=CH-, -CH2-CH2-, and a single bond, and in formula (X) at least one A group or A' group is -CH=CH-;

[0053] (2) reacting the reaction product of step (1) with a compound represented by formula (Y), and collecting the product;

[0054]

[0055] In formula (Y), m is a positive integer between 0 and 10, and the R4' groups in the m repeating units are each independently selected from C1 to C 20 The m T groups are independently selected from —NR”-, C 3～10 The nitrogen-containing heterocyclic group, wherein the R" groups are independently selected from H, C1-C6 straight chain or branched alkyl; R5' groups are selected from H, C1-C 20 A straight chain or branched chain alkyl group.

[0056] According to the preparation method of the present invention, optionally, the C 3～10 The nitrogen-containing heterocyclic group is the same as described above.

[0057] According to the preparation method of the present invention, optionally, in formula (X), the R1' group is selected from H, C1 to C 10 A straight or branched alkyl group, R2' group is C1~C 10 A straight or branched alkylene group, R3' group is selected from C5~C 10 A straight or branched alkyl group; n" is a positive integer between 1 and 5; in formula (Y), m is a positive integer between 0 and 5, and the R4 groups in the m repeating units are each independently selected from C1 to C 10 The m T groups are independently selected from —NR”-, C 3～6 The nitrogen-containing heterocyclic group, wherein the R" groups are independently selected from H, C1-C4 straight chain or branched alkyl; R5 groups are selected from H, C1-C 10 A straight chain or branched chain alkyl group.

[0058] According to the preparation method of the present invention, optionally, in step (1), the molar ratio between the maleic anhydride and the compound represented by formula (X) is 1:0.5-2, preferably 1:0.8-1.5; the temperature at which the maleic acid and / or its anhydride react with the compound represented by formula (X) is 180-280°C, preferably 180-240°C; the pressure at which the maleic acid and / or its anhydride react with the compound represented by formula (X) is 0.5-5MPa, preferably 1-3MPa; the time for the maleic acid and / or its anhydride to react with the compound represented by formula (X) is 6-18h, preferably 6-12h.

[0059] According to the preparation method of the present invention, optionally, in step (2), the molar ratio between the intermediate product of step (1) and the compound represented by formula (Y) is 1:0.3-2, preferably 1:0.4-1.5; the temperature at which the intermediate product of step (1) reacts with the compound represented by formula (Y) is 40-180°C, preferably 50-160°C; the pressure at which the intermediate product of step (1) reacts with the compound represented by formula (Y) can be low pressure, normal pressure or high pressure, and is not particularly limited; the reaction time of the intermediate product of step (1) and the compound represented by formula (Y) is generally as long as possible, generally 0.5-20h, preferably 1-15h.

[0060] According to the preparation method of the present invention, preferably, in step (2), the intermediate product of step (1) is reacted with the compound represented by formula (Y) at 40-90°C for 1-6 hours (preferably at 50-80°C for 2-4 hours), then at 90-115°C for 1-6 hours (preferably at 90-105°C for 2-4 hours), and finally the temperature is raised to 115-180°C (preferably 120°C-160°C) for dehydration to trace amounts.

[0061] According to the preparation method of the present invention, optionally, a solvent is added to the reaction in step (2), and the solvent is preferably a hydrocarbon solvent, more preferably an aromatic solvent, for example, one or more of toluene, o-xylene, m-xylene, p-xylene, xylene and ethylbenzene. The amount of the solvent added can be preferably to promote the smooth progress of the reaction, and there is no particular limitation, for example, it can be 0.5-2 times the total weight of the intermediate product of step (1) and the compound shown in formula (Y). The solvent can be removed by conventional methods in the art after the reaction is completed, such as distillation, rectification method, etc.

[0062] According to the preparation method of the present invention, optionally, the compound represented by formula (X) can be selected from (Z)-9-tetradecenoic acid pentyl ester, (Z)-9-tetradecenoic acid n-hexyl ester, (Z)-9-tetradecenoic acid isohexyl ester, (Z)-9-tetradecenoic acid n-octyl ester, (Z)-9-tetradecenoic acid-2-ethylhexyl ester, (Z)-9-tetradecenoic acid 2-octyldodecyl ester, (Z)-9-tetradecenoic acid 2-decyl-1-tetradecyl ester, (Z)-9-tetradecenoic acid-2,2-dimethyl-1-propyl ester, (Z)-9-tetradecenoic acid-2 -ethyl-1-butyl ester, (Z)-9-hexadecenoic acid pentyl ester, (Z)-9-hexadecenoic acid n-hexyl ester, (Z)-9-hexadecenoic acid isohexyl ester, (Z)-9-hexadecenoic acid n-octyl ester, (Z)-9-hexadecenoic acid-2-ethylhexyl ester, (Z)-9-hexadecenoic acid-2-octyldodecyl ester, (Z)-9-hexadecenoic acid-2-decyl-1-tetradecyl ester, (Z)-9-hexadecenoic acid-2,2-dimethyl-1-propyl ester, (Z)-9-hexadecenoic acid-2-ethyl-1-butyl ester, oleic acid pentyl ester, oleic acid n-hexyl ester , isohexyl oleate, n-octyl oleate, 2-ethylhexyl oleate, 2-octyldodecyl oleate, 2-decyl-1-tetradecyl oleate, 2,2-dimethyl-1-propyl oleate, 2-ethyl-1-butyl oleate, (Z)-13-docosanoic acid pentyl ester, (Z)-13-docosanoic acid n-hexyl ester, (Z)-13-docosanoic acid isohexyl ester, (Z)-13-docosanoic acid n-octyl oleate, (Z)-13-docosanoic acid 2-ethylhexyl ester, (Z)-13-docosanoic acid 2-octyldodecyl ester, (Z)-13-docosanoic acid 2-octyldodecyl ester. One or more of dialkyl esters, (Z)-13-docosenoic acid-2-decyl-1-tetradecyl ester, (Z)-13-docosenoic acid-2,2-dimethyl-1-propyl ester and (Z)-13-docosenoic acid-2-ethyl-1-butyl ester, preferably one or more of n-hexyl oleate, isohexyl oleate, n-octyl oleate, 2-ethylhexyl oleate, 2-octyldodecyl oleate, 2-decyl-1-tetradecyl oleate, 2,2-dimethyl-1-propyl oleate and 2-ethyl-1-butyl oleate.

[0063] According to the preparation method of the present invention, optionally, the compound represented by formula (Y) can be selected from tert-octylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N,N'-bis(3-aminopropyl)-1,2-ethylenediamine, N,N'-bis(3-aminopropyl)-1,3-propylenediamine, 3,3'-diaminodipropylamine, 4-aminomorpholine, 3-methyl-4-aminomorpholine, 4-(2-aminomethyl)morpholine, 4-(2-aminoethyl)morpholine, 3-methyl-4-(2-aminoethyl)morpholine, N-(3-aminopropyl)morpholine, 4-morpholinebutylamine, 1,4-bis-(3-aminopropyl)piperazine, N-(3-aminopropyl)piperazine, 1,4-piperazinediethylamine, 1-(2-aminoethyl)piperazine, One or more of 2-methyl-1-(2-aminoethyl)piperazine, 1,4-piperazinedimethylamine, piperazine-1-methylamine, 1,4-diaminopiperazine, 2-methyl-1,4-piperazinediamine, thiomorpholine-4-methylamine, 4-(2-aminoethyl)thiomorpholine, 4-(3-aminopropyl)thiomorpholine, 2-(2-methylpiperazin-1-yl)-1-ethylamine, 2-methyl-2-(4-morpholine)propylamine, 2-(2-methylmorpholine-4-yl)ethane-1-amine, preferably one or more of tetraethylenepentamine, pentaethylenehexamine, 3,3'-diaminodipropylamine, 4-(2-aminoethyl)morpholine, 1,4-bis-(3-aminopropyl)piperazine, N-(3-aminopropyl)piperazine and 1-(2-aminoethyl)piperazine.

[0064] According to the preparation method of the present invention, preferably, the reaction of step (1) and / or step (2) is carried out under the protection of an inert gas, and the inert gas may be nitrogen or argon.

[0065] According to the preparation method of the present invention, optionally, after the reaction of step (1) and / or step (2) is completed, the reaction product can be purified, and the purification method includes one or more of water washing, distillation, rectification, molecular distillation, filtration, drying and recrystallization methods, without special limitation.

[0066] According to the preparation method of the present invention, as a reaction product, a single imide compound can be prepared, and a mixture consisting of multiple imide compounds can also be prepared. These reaction products are all expected by the present invention, and the difference in their existence forms does not affect the realization of the effect of the present invention. Therefore, in the context of this specification, these reaction products are all collectively referred to as imide compounds without distinction. In view of this, according to the present invention, there is no absolute necessity to further purify the reaction product, or to further separate an imide compound of a certain specific structure from the reaction product. Of course, the purification or separation is preferred for further improvement of the expected effect of the present invention, but is not necessary for the present invention. Nevertheless, as the purification or separation method, for example, the reaction product can be purified or separated by a column chromatography method or a preparative chromatography method.

[0067] The preparation method of the invention has simple process, safe and readily available raw materials, renewable, mild conditions, and is safe and non-toxic.

[0068] The imide compound of the present invention and the imide compound prepared by the preparation method of the present invention can be used as a diesel antiwear agent.

[0069] The imide compound of the present invention and the imide compound prepared according to the preparation method of the present invention have excellent anti-wear and anti-corrosion properties and can improve the lubricity and anti-corrosion properties of diesel.

[0070] The present invention also provides a diesel composition, comprising a base diesel, an imide compound or an imide compound prepared according to the above method, wherein the mass of the imide compound or the imide compound prepared according to the above method relative to the base diesel is preferably 50 to 500 mg / kg, more preferably 100 to 400 mg / kg.

[0071] The diesel fuel composition of the present invention has excellent anti-wear and anti-corrosion properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 This is the infrared spectrum of oleic acid-2-ethylhexyl succinic anhydride in Example 1 of the present invention.

[0073] Figure 2 This is the mass spectrum of 2-ethylhexyl oleate succinic anhydride in Example 1 of the present invention.

[0074] Figure 3 This is the infrared spectrum of 2-ethylhexyl stearate succinic anhydride in Example 2 of the present invention.

[0075] Figure 4 This is the mass spectrum of 2-ethylhexyl stearate succinic anhydride in Example 2 of the present invention.

[0076] Figure 5 This is the infrared spectrum of product 1 in Example 1 of the present invention.

[0077] Figure 6 It is the mass spectrum of product 1 in Example 1 of the present invention.

[0078] Figure 7 This is the infrared spectrum of product 2 in Example 2 of the present invention.

[0079] Figure 8 It is the mass spectrum of product 2 in Example 2 of the present invention. DETAILED DESCRIPTION

[0080] The present invention is explained and illustrated below through specific implementation modes, but it does not constitute a limitation of the present invention.

[0081] In the context of this specification, the term "single bond" is sometimes used in the definition of a group. The so-called "single bond" means that the group does not exist. For example, assume the structural formula -CH2-A-CH3, where the group A is defined as being selected from a single bond and a methyl group. In view of this, if A is a single bond, it means that the group A does not exist, and the structural formula is then simplified to -CH2-CH3 accordingly.

[0082] Taking oleate as an example, the reaction equation of step (1) of the present invention can be shown as follows:

[0083]

[0084] After the above reaction, the product obtained in step (1) of the present invention includes product A, product B, product C, and product D, which is a mixture. This mixture can be used for the next reaction without separation.

[0085] Taking a primary amine having only one amine group in its molecule and the product C obtained in step (1) as an example, the reaction equation of step (2) of the present invention is as follows:

[0086]

[0087] Therefore, after the above reaction, the product obtained in the present invention may include a variety of imide compounds, which is a mixture. This mixture is the isomers of a variety of monounsaturated fatty acid ester succinimide compounds.

[0088] Taking a primary amine containing two amine groups in its molecule and the product C obtained in step (1) as an example, the reaction equation of step (2) of the present invention is as follows:

[0089]

[0090] Therefore, after the above reaction, the product obtained in the present invention is usually an imide compound including multiple isomers, which is a mixture.

[0091] Main raw materials used and their sources:

[0092] Methyl oleate (85%, Aladdin Industrial Corporation), 2-ethylhexanol (99%, AladdinIndustrial Corporation), 2-octyldodecanol (Aladdin Industrial Corporation), potassium carbonate (AR, Tianjin Damao Chemical Reagent Factory), maleic anhydride (99.5%, Innochem), 4-(2-aminoethyl)morpholine (99%, Adamas-beta), 1-(2-aminoethyl)piperazine (99%, Aladdin Industrial Corporation), tert-octylamine (95%, Acros Organics), triethylenetetramine (60%, Acros Organics), 1,4-bis-(3-aminopropyl)piperazine (98%, Tokyo Chemical industry), tetraethylenepentamine (Acros Organics), toluene (AR, Tianjin Damao Chemical Reagent Factory), o-xylene (AR, Tianjin Damao Chemical Reagent Factory), T531 (N-phenyl α-naphthylamine) (Tianjin Wuyi Chemical Factory), V81 (4,4-di-tert-octyl diphenylamine) (Vanderbilt Company), T706 (benzotriazole) (Nanjing Ningjiang Chemical Factory), TCP (tricresyl phosphate) (Shandong Qingyun Tianbin Chemical Co., Ltd.), DF-06 blending oil (Shandong Hengyuan Petrochemical Group Co., Ltd.)

[0093] Example 1

[0094] The main raw materials include: methyl oleate, 2-ethylhexanol, potassium carbonate, maleic anhydride, 1-(2-aminoethyl)piperazine, and o-xylene.

[0095] The reaction steps for preparing the imide compounds of the present invention are as follows:

[0096] (1) Using potassium carbonate as a catalyst, 941.82 g of methyl oleate with a purity of 85% and 1065.54 g of 2-ethylhexanol with a purity of 99% were subjected to an ester exchange reaction at 170° C. until no liquid condensed in the water separator. After the reaction, the potassium carbonate was removed by filtration and the 2-ethylhexanol was removed by reduced pressure distillation to obtain 2-ethylhexyl oleate with a purity of more than 82%.

[0097] (2) 287.98 g of 2-ethylhexyl oleate with a purity of 82.23% and 88.70 g of maleic anhydride with a purity of 99.5% were added to an autoclave equipped with stirring and forced circulation, nitrogen was introduced to exhaust the air in the autoclave, the pressure of the reaction system was first increased to 1 MPa, the temperature of the reaction system was increased to 200° C., and then the pressure of the reaction system was increased to 2 MPa, and the reaction was carried out at this pressure and temperature for 10 hours; after the reaction was completed, unreacted maleic anhydride and 2-ethylhexyl oleate were removed by reduced pressure distillation to obtain 2-ethylhexyl oleate succinic anhydride with a purity of more than 90%, and the structure of 2-ethylhexyl oleate succinic anhydride was determined by infrared spectrometry and gas chromatography-mass spectrometry.

[0098] (3) Add an o-xylene solution of 2-ethylhexyl oleate succinic anhydride (48.20 g of 2-ethylhexyl oleate succinic anhydride synthesized in step (2) + 50 g of o-xylene) into a three-necked flask, install a mechanical stirrer, a nitrogen conduit and a constant pressure dropping funnel; prepare an o-xylene solution of 1-(2-aminoethyl)piperazine (23.26 g of 1-(2-aminoethyl)piperazine + 23.68 g of o-xylene), pour in a constant pressure dropping funnel, and add 1-(2-aminoethyl)piperazine in an o-xylene solution. funnel; place the three-necked flask in a 5°C constant temperature oil bath, start mechanical stirring and pass nitrogen for 30 minutes; stop passing nitrogen, and drop 1-(2-aminoethyl)piperazine in o-xylene solution into the three-necked flask; after the dropwise addition is completed, remove the constant pressure dropping funnel and replace it with a water separator and condenser filled with o-xylene, raise the temperature of the oil bath to 60°C and keep the temperature constant for 1h, then raise the temperature to 90°C and keep the temperature constant for 4h, and finally raise the temperature to 160°C and dehydrate to trace amounts. The reaction mixture is rotary evaporated to remove o-xylene to obtain product 1.

[0099] After analysis, the structural formula of product 1 is as follows:

[0100]

[0101] The infrared spectra of oleic acid 2-ethylhexyl ester succinic anhydride and product 1 were determined. Figure 1 and Figure 5 .

[0102] The infrared spectrum measurement conditions are as follows: Instrument model: NICOLET IS50 from Thermo Fisher Scientific, USA, Instrument parameters: Scan times 16 times, resolution 4 cm -1 , scanning range 4000-400cm -1 , liquid sample smear method, solid sample compression method.

[0103] exist Figure 1 Medium, 1863cm -1 and 1785cm -1 It is the asymmetric and symmetric stretching vibration peak of the carbonyl C=O of the cyclic anhydride, 1221cm -1The COC stretching vibration peak of cyclic anhydride is 1735 cm -1 is the stretching vibration peak of the ester carbonyl C=O, 976cm -1 It is the out-of-plane bending vibration peak of the double bond = CH trans configuration. The infrared spectrum shows that there are cyclic anhydride groups, double bonds and ester groups in oleic acid-2-ethylhexyl ester succinic anhydride, indicating that oleic acid-2-ethylhexyl ester succinic anhydride has been successfully synthesized.

[0104] exist Figure 5 Medium, 1774cm -1 and 1704cm -1 It is the asymmetric and symmetric stretching vibration peak of the cyclic imide carbonyl C=O, 1736cm -1 is the stretching vibration peak of the ester carbonyl C=O, 976cm -1 is the out-of-plane bending vibration peak of the double bond =CH trans configuration, and 1863cm -1 and 1785cm -1 No peak was obtained. The infrared spectrum showed that the product 1 contained cyclic imide groups, double bonds and ester groups, and the cyclic anhydride groups disappeared, indicating that the product 1 was successfully synthesized.

[0105] The oleic acid 2-ethylhexyl ester succinic anhydride was determined by gas chromatography-mass spectrometry. Figure 2 .

[0106] The gas chromatography-mass spectrometry conditions are as follows:

[0107] Instrument model: Agilent 7890-5975 chromatographic column HP-SMS (30m×250μm×0.25μm). Experimental conditions: injection volume 0.5μL, pressure 126.44kPa, total flow rate 79.5mL / min, split ratio 50:1, split flow rate 75mL / min, chromatographic column 1 (pressure 126.44kPa, flow rate 1.5mL / min, average velocity 30.794cm / s), chromatographic column 2 (pressure 26.20kPa, flow rate 5.0454mL / min, average velocity 255.78cm / s).

[0108] Figure 2 The peak at 492.4 is the molecular ion peak of 2-ethylhexyl oleate succinic anhydride.

[0109] The product 1 was analyzed by mass spectrometry. Figure 6 .

[0110] The mass spectrometry conditions are as follows:

[0111] Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS), model Bruker SolariX XR, magnetic field strength 15T. Experimental conditions: injection rate 120μL / h, electrospray ion source, positive ion mode (ESI+), capillary voltage 4500V, nebulizer 1bar, drying gas flow rate 4.0L / min, dryer temperature 200℃, TOF 0.6ms, Q1 mass 150u, RF 800Vpp, front and rear baffle voltage 1.8V, SEP (Sweep Excitation Power) 15, mass-to-charge ratio (m / z) detection range 50-1500, cumulative scanning 64 times during sampling. Sample preparation: Prepare about 0.1mg / mL sample with chromatographic pure methanol.

[0112] Figure 6 604.5070 is product 1 combined with one H + molecular ion peak.

[0113] Example 2

[0114] The main raw materials include: methyl oleate, potassium carbonate, 2-ethylhexanol, maleic anhydride, 1-(2-aminoethyl)piperazine, and o-xylene.

[0115] The reaction steps for preparing the imide compounds of the present invention are as follows:

[0116] (1) Using potassium carbonate as a catalyst, 627.88 g of methyl oleate with a purity of 85% and 710.36 g of 2-ethylhexanol with a purity of 99% were subjected to an ester exchange reaction at 170° C. until no liquid condensed in the water separator. After the reaction, the potassium carbonate was removed by filtration and the 2-ethylhexanol was removed by reduced pressure distillation to obtain 2-ethylhexyl oleate with a purity of more than 82%.

[0117] (2) 287.98 g of 2-ethylhexyl oleate with a purity of 82.23% and 88.70 g of maleic anhydride with a purity of 99.5% were added to an autoclave with stirring and forced circulation, the air tightness was checked, nitrogen was introduced to exhaust the air in the autoclave, the pressure of the reaction system was first increased to 1 MPa, the temperature of the reaction system was increased to 200° C., and then the pressure of the reaction system was increased to 3 MPa, and the reaction was carried out at this pressure and temperature for 6 hours; after the reaction was completed, unreacted maleic anhydride and 2-ethylhexyl oleate were removed by reduced pressure distillation to obtain 2-ethylhexyl oleate succinic anhydride with a purity of more than 90%.

[0118] (3) 200 g of oleic acid 2-ethylhexyl succinic anhydride with a purity of more than 90% obtained in step (2) and 2 g of 10% palladium-carbon catalyst were added to an autoclave with stirring and forced circulation, the airtightness was checked, 3 MPa of hydrogen was introduced, the temperature of the reaction system was raised to 100° C., and the reaction was carried out at this pressure and temperature for 6 hours. After the reaction was completed, o-xylene as a diluent was added, the palladium-carbon catalyst was filtered out, and the o-xylene was removed by a rotary evaporator to obtain stearic acid 2-ethylhexyl succinic anhydride with a purity of more than 90%. The structure of stearic acid 2-ethylhexyl succinic anhydride was determined by infrared spectrometry and gas chromatography-mass spectrometry.

[0119] (4) Add a solution of 2-ethylhexyl stearate succinic anhydride in o-xylene (44.53 g of 2-ethylhexyl stearate succinic anhydride synthesized in step (3) + 50 g of o-xylene) into a three-necked flask, install a mechanical stirrer, a nitrogen duct and a constant pressure dropping funnel; prepare a solution of 1-(2-aminoethyl)piperazine in o-xylene (23.26 g of 1-(2-aminoethyl)piperazine + 23.68 g of o-xylene), pour in a constant pressure dropping funnel, and add 1-(2-aminoethyl)piperazine in o-xylene. The three-necked flask was placed in a 5°C constant temperature oil bath, mechanical stirring was started and nitrogen was passed for 30 minutes; nitrogen was stopped, and the o-xylene solution of 1-(2-aminoethyl)piperazine was added dropwise to the three-necked flask; after the addition was completed, the constant pressure dropping funnel was removed and replaced with a water separator and condenser filled with o-xylene, the oil bath was heated to 60°C and kept at this temperature for 1 hour, then heated to 90°C and kept at this temperature for 4 hours, and finally heated to 160°C and dehydrated to trace amounts. The o-xylene was removed from the reaction mixture by rotary evaporation to obtain product 2.

[0120] After analysis, the structural formula of product 2 is as follows:

[0121]

[0122] The infrared spectra of stearic acid 2-ethylhexyl succinic anhydride and product 2 were determined. Figure 3 and Figure 7 .

[0123] The infrared spectrum measurement conditions are the same as those in Example 1.

[0124] exist Figure 3 Medium, 1863cm -1 and 1785cm -1 It is the asymmetric and symmetric stretching vibration peak of the carbonyl C=O of the cyclic anhydride, 1221cm -1 The COC stretching vibration peak of cyclic anhydride is 1735 cm -1The peak of the stretching vibration of the carbonyl group C=O of the ester does not appear, and the out-of-plane bending vibration peak of the double bond =CH trans configuration at 976cm-1 does not appear. The infrared spectrum shows that there are cyclic anhydride groups and ester groups in stearic acid-2-ethylhexyl ester succinic anhydride, indicating that stearic acid-2-ethylhexyl ester succinic anhydride has been successfully synthesized.

[0125] exist Figure 7 Medium, 1774cm -1 and 1704cm -1 It is the asymmetric and symmetric stretching vibration peak of the cyclic imide carbonyl C=O, 1736cm -1 is the stretching vibration peak of the ester carbonyl C=O, and 1863cm -1 and 1785cm -1 No peak was obtained. The infrared spectrum showed that the product 2 contained cyclic imide groups and ester groups, and the cyclic anhydride groups disappeared, indicating that the product 2 was successfully synthesized.

[0126] Stearic acid 2-ethylhexyl ester succinic anhydride was determined by gas chromatography-mass spectrometry. Figure 4 .

[0127] The measurement conditions of gas chromatography-mass spectrometry are the same as those of gas chromatography-mass spectrometry in Example 1.

[0128] Figure 4 The peak at 494.3 is the molecular ion peak of 2-ethylhexyl stearate succinic anhydride.

[0129] The product 2 was analyzed by mass spectrometry. Figure 8 .

[0130] The mass spectrometry measurement conditions were the same as those in Example 1.

[0131] Figure 8 606.5210 is product 2 combined with one H + molecular ion peak.

[0132] Example 3

[0133] The main raw materials include: methyl oleate, potassium carbonate, 2-ethylhexanol, maleic anhydride, 1,4-bis(3-aminopropyl)piperazine, and toluene.

[0134] The reaction steps for preparing the imide compounds of the present invention are as follows:

[0135] (1) Using potassium carbonate as a catalyst, 941.82 g of methyl oleate with a purity of 85% and 1065.54 g of 2-ethylhexanol with a purity of 99% are transesterified at 170° C. until no liquid condenses in the water separator. After the reaction is completed, the potassium carbonate is removed by filtration and the 2-ethylhexanol is removed by reduced pressure distillation to obtain 2-ethylhexyl oleate with a purity of more than 82%.

[0136] (2) 287.98 g of 2-ethylhexyl oleate with a purity of 82.23% and 88.70 g of maleic anhydride with a purity of 99.5% were added to an autoclave equipped with stirring and forced circulation, and nitrogen was introduced to exhaust the air in the autoclave. The pressure of the reaction system was first increased to 1 MPa, the temperature of the reaction system was increased to 200° C., and then the pressure of the reaction system was increased to 2.5 MPa, and the reaction was carried out at this pressure and temperature for 8 hours. After the reaction was completed, unreacted maleic anhydride and 2-ethylhexyl oleate were removed by reduced pressure distillation to obtain 2-ethylhexyl oleate succinic anhydride with a purity of more than 90%, and the structure of methyl oleate succinic anhydride was determined by infrared spectrometry and gas chromatography-mass spectrometry.

[0137] (3) Add a toluene solution of 2-ethylhexyl oleate succinic anhydride (48.20 g of 2-ethylhexyl oleate succinic anhydride synthesized in step (2) + 50 g of toluene) into a three-necked flask, install a mechanical stirrer, a nitrogen conduit and a constant pressure dropping funnel; prepare a toluene solution of 1,4-bis(3-aminopropyl)piperazine (11.84 g of 1,4-bis(3-aminopropyl)piperazine + 23.68 g of toluene), pour in a constant pressure dropping funnel, and add 10% ethanol. funnel; place the three-necked flask in a 5℃ constant temperature oil bath, start mechanical stirring and pass nitrogen for 30 minutes; stop passing nitrogen, and drop 1,4-bis(3-aminopropyl)piperazine toluene solution into the three-necked flask; after the dropwise addition is completed, remove the constant pressure dropping funnel and replace it with a water separator and condenser filled with toluene, raise the oil bath temperature to 60℃ and keep the temperature constant for 2h, then raise the temperature to 80℃ and keep the temperature constant for 4h, and finally raise the temperature to 120℃ and dehydrate to trace amounts. The reaction mixture is evaporated to remove toluene to obtain product 3.

[0138] After analysis, the structural formula of product 3 is as follows:

[0139]

[0140] Example 4

[0141] The main raw materials include: methyl oleate, potassium carbonate, 2-octyl-dodecanol, maleic anhydride, 1-(2-aminoethyl)piperazine, and toluene.

[0142] The reaction steps for preparing the imide compounds of the present invention are as follows:

[0143] (1) Using potassium carbonate as a catalyst, 732.50 g of methyl oleate with a purity of 85% and 1393.28 g of 2-octyl-dodecanol with a purity of 99% are subjected to an ester exchange reaction at 220° C. until no liquid condenses in the water separator. After the reaction is completed, the potassium carbonate is removed by filtration and the 2-octyl-dodecanol is removed by reduced pressure distillation to obtain 2-n-octyl-dodecyl oleate with a purity of more than 82%.

[0144] (2) 102.99 g of 2-n-octyl-dodecyl oleate with a purity of 82.00% and 22.17 g of maleic anhydride with a purity of 99.5% were added to an autoclave with stirring and forced circulation, nitrogen was introduced to exhaust the air in the autoclave, the pressure of the reaction system was first increased to 1 MPa, the temperature of the reaction system was increased to 200° C., and then the pressure of the reaction system was increased to 3 MPa, and the reaction was carried out at this pressure and temperature for 12 hours; after the reaction was completed, unreacted maleic anhydride and 2-n-octyl-dodecyl oleate were removed by reduced pressure distillation to obtain 2-n-octyl-dodecyl oleate succinic anhydride with a purity of more than 90%, and the structure of 2-n-octyl-dodecyl oleate succinic anhydride was determined by infrared spectrometry and liquid chromatography-mass spectrometry.

[0145] (3) Add a toluene solution of 2-octyl-dodecyl oleate succinic anhydride (66.06 g of 2-octyl-dodecyl oleate succinic anhydride synthesized in step (2) + 50 g of toluene) into a three-necked flask, install a mechanical stirrer, a nitrogen conduit and a constant pressure dropping funnel; prepare a toluene solution of 1-(2-aminoethyl)piperazine (11.84 g of 1-(2-aminoethyl)piperazine + 23.68 g of toluene), and pour into a constant pressure flask. The three-necked flask was placed in a 5°C constant temperature oil bath, mechanical stirring was started and nitrogen was passed for 30 minutes; nitrogen was stopped, and a toluene solution of 1-(2-aminoethyl)piperazine was added dropwise to the three-necked flask; after the addition was completed, the constant pressure dropping funnel was removed and replaced with a water separator and condenser filled with toluene, the oil bath was heated to 50°C and kept at this temperature for 1 hour, then heated to 80°C and kept at this temperature for 4 hours, and finally heated to 120°C and dehydrated to trace amounts. The mixture after the reaction was evaporated to remove toluene to obtain product 4.

[0146] After analysis, the structural formula of product 4 is as follows:

[0147]

[0148] Example 5

[0149] The main raw materials include: methyl oleate, potassium carbonate, 2-octyl-dodecanol, maleic anhydride tetraethylenepentamine, and toluene.

[0150] The reaction steps for preparing the imide compounds of the present invention are as follows:

[0151] (1) Using potassium carbonate as a catalyst, 732.50 g of methyl oleate with a purity of 85% and 1393.28 g of 2-octyl-dodecanol with a purity of 99% are transesterified at 220° C. until no liquid condenses in the water separator. After the reaction is completed, the potassium carbonate is removed by filtration and the 2-octyl-dodecanol is removed by reduced pressure distillation to obtain 2-n-octyl-dodecyl oleate with a purity of more than 82%.

[0152] (2) 102.99 g of 2-n-octyl-dodecyl oleate with a purity of 82.00% and 22.17 g of maleic anhydride with a purity of 99.5% were added to an autoclave with stirring and forced circulation, nitrogen was introduced to exhaust the air in the autoclave, the pressure of the reaction system was first increased to 1 MPa, the temperature of the reaction system was increased to 200° C., and then the pressure of the reaction system was increased to 3 MPa, and the reaction was carried out at this pressure and temperature for 12 hours; after the reaction was completed, unreacted maleic anhydride and 2-n-octyl-dodecyl oleate were removed by reduced pressure distillation to obtain 2-n-octyl-dodecyl oleate succinic anhydride with a purity of more than 90%, and the structure of 2-n-octyl-dodecyl oleate succinic anhydride was determined by infrared spectrometry and liquid chromatography-mass spectrometry.

[0153] (3) Add a toluene solution of 2-octyl-dodecyl oleate succinic anhydride (66.06 g of 2-octyl-dodecyl oleate succinic anhydride synthesized in step (2) + 50 g of toluene) to a three-necked flask, install a mechanical stirrer, a nitrogen conduit and a constant pressure dropping funnel; prepare a toluene solution of tetraethylene pentamine (17.04 g of tetraethylene pentamine + 34.07 g of toluene), and pour it into the constant pressure dropping funnel; place the three-necked flask in a 5°C constant temperature oil bath, start mechanical stirring and pass nitrogen for 30 minutes; stop passing nitrogen, and drop the toluene solution of tetraethylene pentamine into the three-necked flask; after the dropwise addition is completed, remove the constant pressure dropping funnel and replace it with a water separator and condenser filled with toluene, raise the temperature of the oil bath to 50°C and keep the temperature constant for 2 hours, then raise the temperature to 80°C and keep the temperature constant for 2 hours, and finally raise the temperature to 120°C to dehydrate to trace amounts. The mixture after the reaction was evaporated to remove toluene to obtain product 5.

[0154] After analysis, the structural formula of product 5 is as follows:

[0155]

[0156] Comparative Example 1

[0157] Tall oil fatty acid, an acidic anti-wear agent commonly used in diesel, was selected as comparative additive 1, specifically tall oil fatty acid with a product code of 2LT produced by Arizonal Corporation.

[0158] Comparative Example 2

[0159] Methyl oleate (mass fraction 85%, Aladdin Industrial Corporation) was selected as comparative additive 2.

[0160] Comparative Example 3

[0161] Oleic acid (mass fraction 85%, Aladdin Industrial Corporation) was selected as comparative additive 3.

[0162] Evaluation test

[0163] The lubricating effects of products 1, 2, 3, 4, 5 and comparative additives 1, 2, 3 in low sulfur diesel were evaluated using the HFRR method (ISO 12156-1:2016).

[0164] The products 1, 2, 3, 4, 5 and comparative additives 1, 2, 3 were blended with base diesel to obtain diesel compositions of Examples I-1 to I-10 and Comparative Examples DI-1 to DI-6. The base diesel was DF-06 blending oil, and its physical and chemical properties are shown in Table 1.

[0165] Table 1 Physical and chemical properties of DF-6 blended oil

[0166] project Numeric <![CDATA[Density (20 °C) / (g / cm 3 )]]> 0.8298 <![CDATA[Viscosity (20 °C) / (mm 2 / s)]]> 3.229 Sulfur content / (mg / kg) 0.5 Alkanes / (m%) 44.8 Total cycloalkanes / (m%) 31.6 Total monocyclic aromatic hydrocarbons / (m%) 21.9 Total bicyclic aromatic hydrocarbons / (m%) 1.7 Tricyclic aromatic hydrocarbons / (m%) 0 Initial distillation point / (℃) 193 20% boiling point / (℃) 226 50% boiling point / (℃) 249 90% boiling point / (℃) 276 Dry point / (℃) 286 Average wear spot diameter WSD / (μm) 586.5

[0167] The numbers and compositions of the test diesel compositions are shown in Table 2, and the average wear spot diameter (WSD) results obtained by HFRR tests (test temperature is 60°C) on these diesel compositions are also shown in Table 2. When the average wear spot diameter (WSD) is less than 460 μm, the lubricity of the diesel is qualified.

[0168] Table 2

[0169]

[0170] It can be seen from Table 2 that the addition of the imide compound of the present invention can greatly improve the lubricity of diesel.

[0171] Corrosion resistance evaluation

[0172] The anti-corrosion effects of products 1, 2, 3, 4, 5 and comparative additives 1, 2, 3 in low-sulfur diesel were evaluated using the GB / T 11143 method.

[0173] Add 200mg / kg of additives to DF-06 blended oil to evaluate the anti-corrosion performance of the additives. Test method GB / T 11143 stipulates the determination method of the anti-rust performance of inhibitor mineral oil in the presence of water. The specific method is: mix 300mL of sample with 30mL of distilled water or synthetic seawater, immerse the cylindrical test steel rod in it, and stir at 60℃. The test cycle is 4h, 8h, and 24h. After the test cycle, observe the traces and degree of rust on the test steel rod.

[0174] The results of the corrosion resistance test are shown in Table 3.

[0175] Table 3 Corrosion resistance test results

[0176] additive Corrosion / 100% corrosion within 4 hours Product 1 24 hours no corrosion Product 2 24 hours no corrosion Product 3 24 hours no corrosion Product 4 24 hours no corrosion Product 5 24 hours no corrosion Comparative Example 1 10% corrosion within 8 hours Comparative Example 2 20% corrosion within 4 hours Comparative Example 3 25% corrosion within 4 hours

[0177] It can be seen from Table 3 that the addition of the imide compound synthesized by the present invention has a significant improvement effect on the rust of diesel, and the effect is significantly better than that of the comparative example.

[0178] The above embodiments are only used to illustrate the technical solutions of the embodiments of the present disclosure, rather than to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein.

Claims

1. An imide compound, the structure of which is shown in formula (I): In formula (I), the R1 group is selected from H, C1 to C 20 A straight or branched alkyl group, R2 group is C1~C 20 A straight or branched alkylene group, R3 group is selected from C5~C 24 A straight chain or branched alkyl group; n is 1, and the A group and the A' group are each independently selected from -CH=CH-, -CH2-CH2-, and a single bond; The G group is selected from the group represented by formula (II); In formula (II), * represents the binding end bonded to formula (I); The G' group in formula (II) is selected from the group shown in formula (III); In formula (III), * represents the binding end bonded to the nitrogen atom in formula (II); m is 1, and the R4 group is selected from C1 to C 20 A straight or branched alkylene group, wherein the T group is selected from -NR"-, C 3～10 A nitrogen-containing heterocyclic group, wherein the R" group is selected from H, C1-C6 straight chain or branched alkyl; the R5 group is selected from H, C1-C 20 A straight chain or branched alkyl group, a group represented by formula (IV); In formula (IV), the R1 group is selected from H, C1 to C 20 A straight or branched alkyl group, R2 group is C1~C 20 A straight or branched alkylene group, R3 group is selected from C5~C 24 A straight chain or branched alkyl group; n' is 1, and the A group and the A' group are each independently selected from -CH=CH-, -CH2-CH2-, and a single bond; G" group is selected from H, C1~C 20 A straight or branched alkyl group, a group represented by formula (V), in formula (IV), there is a G" group selected from the group represented by formula (V); In formula (V), * represents the bonding end bonded to formula (IV), and △ represents the bonding end bonded to formula (III).

2. The imide compound according to claim 1, characterized in that: In formula (I), the R1 group is selected from H, C1 to C 10 A straight or branched alkyl group, R2 group is C1~C 10 A straight or branched alkylene group, R3 group is selected from C5~C 20 In formula (III), the R4 groups in the m repeating units are independently selected from C1 to C 10 The m T groups are independently selected from —NR”-, C 3～6 A nitrogen-containing heterocyclic group, wherein the R" groups are independently selected from H, C1-C4 straight chain or branched alkyl; in formula (IV), the R1 group is selected from H, C1-C 10 A straight or branched alkyl group, R2 group is C1~C 10 A straight or branched alkylene group, R3 group is selected from C5~C 20 The G" groups in the n'repeating units are each independently selected from H, C1~C 10 A straight chain or branched alkyl group, a group represented by formula (V).

3. The imide compound according to claim 1, characterized in that: The C 3～10 The nitrogen-containing heterocyclic group is a nitrogen-containing heterocyclic group obtained by removing two H from the nitrogen-containing heterocyclic compound represented by formula (VI); In formula (VI), R I The group is a C1-C9 straight chain or branched alkylene group, R II The group is a C1-C9 straight chain or branched alkylene group, R I Group and R II The sum of the carbon atoms of the group is an integer between 3 and 10; the D group is -O-, -S- or -NR"-, wherein the R" group is selected from H, a C1-C4 straight chain or branched alkyl group.

4. The imide compound according to claim 1, characterized in that: The nitrogen-containing heterocyclic compound represented by formula (VI) includes one or more of the following compounds: 4-aminomorpholine, 3-methyl 4-aminomorpholine, 4-(2-aminomethyl)morpholine, 4-(2-aminoethyl)morpholine, 3-methyl-4-(2-aminoethyl)morpholine, N-(3-aminopropyl)morpholine, 4-morpholinebutylamine, 1,4-bis-(3-aminopropyl)piperazine, N-(3-aminopropyl)piperazine, 1,4-piperazinediethylamine, 1-(2-aminoethyl)morpholine Piperazine, 2-methyl-1-(2-aminoethyl)piperazine, 1,4-piperazinedimethylamine, piperazine-1-methylamine, 1,4-diaminopiperazine, 2-methyl-1,4-piperazinediamine, 2-(2-methylpiperazin-1-yl)-1-ethylamine, 2-methyl-2-(4-morpholino)propylamine, 2-(2-methylmorpholin-4-yl)ethane-1-amine, thiomorpholine-4-methylamine, 4-(2-aminoethyl)thiomorpholine, 4-(3-aminopropyl)thiomorpholine.

5. The imide compound according to claim 1, characterized in that: The imide compound is a compound of the following types or a composition obtained by combining them in any proportion: or / and 6. The imide compound according to claim 1, characterized in that: The imide compound is any one of the following single compounds or a composition obtained by combining the single compounds in any proportion:

7. A method for preparing an imide compound, comprising: (1) a step of reacting maleic anhydride with a compound represented by formula (X); In formula (X), the R1' group is selected from H, C1-C 20 A straight or branched alkyl group, R2' group is C1~C 20 A straight or branched alkylene group, R3' group is selected from C5~C 24 A straight chain or branched alkyl group; n" is 1, the A group and the A' group are each independently selected from -CH=CH-, -CH2-CH2-, a single bond, and in formula (X) at least one A group or A' group is -CH=CH-; (2) reacting the reaction product of step (1) with a compound represented by formula (Y), and collecting the product; In formula (Y), m is 1, and the R4' group is selected from C1 to C 20 A straight or branched alkylene group, wherein the T group is selected from -NR"-, C 3～10 A nitrogen-containing heterocyclic group, wherein the R" group is selected from H, C1-C6 straight chain or branched alkyl; the R5' group is selected from H, C1-C 20 A straight chain or branched chain alkyl group.

8. The method according to claim 7, characterized in that The C 3～10 The nitrogen-containing heterocyclic group is a nitrogen-containing heterocyclic group obtained by removing two H from the nitrogen-containing heterocyclic compound represented by formula (VII); In formula (VII), R I The group is a C1-C9 straight chain or branched alkylene group, R II The group is a C1-C9 straight chain or branched alkylene group, R I Group and R II The sum of the carbon atoms of the group is an integer between 3 and 10; the D group is -O-, -S- or -NR"-, wherein the R" group is selected from H, a C1-C4 straight chain or branched alkyl group.

9. The method according to claim 7, characterized in that In formula (X), the R1' group is selected from H, C1-C 10 A straight or branched alkyl group, R2' group is C1~C 10 A straight or branched alkylene group, R3' group is selected from C5~C 10 In formula (Y), the R4 groups in the m repeating units are independently selected from C1 to C 10 The m T groups are independently selected from —NR”-, C 3～6 The nitrogen-containing heterocyclic group, wherein the R" groups are independently selected from H, C1-C4 straight chain or branched alkyl; R5 groups are selected from H, C1-C 10 A straight chain or branched chain alkyl group.

10. The method according to claim 7, characterized in that In step (1), the molar ratio of maleic anhydride to the compound represented by formula (X) is 1:0.5-2; the temperature at which maleic acid and / or its anhydride react with the compound represented by formula (X) is 180-280°C; the pressure at which maleic acid and / or its anhydride react with the compound represented by formula (X) is 0.5-5MPa; the time for which maleic acid and / or its anhydride react with the compound represented by formula (X) is 6-18h; In step (2), the molar ratio between the intermediate product of step (1) and the compound represented by formula (Y) is 1:0.3-2; the temperature for the reaction between the intermediate product of step (1) and the compound represented by formula (Y) is 40-180°C; the time for the reaction between the intermediate product of step (1) and the compound represented by formula (Y) is 0.5-20h.

11. The method according to claim 7, characterized in that In step (1), the molar ratio of maleic anhydride to the compound represented by formula (X) is 1:0.8-1.5; the temperature at which maleic acid and / or its anhydride react with the compound represented by formula (X) is 180-240°C; the pressure at which maleic acid and / or its anhydride react with the compound represented by formula (X) is 1-3 MPa; the time for which maleic acid and / or its anhydride react with the compound represented by formula (X) is 6-12 hours; In step (2), the molar ratio between the intermediate product of step (1) and the compound represented by formula (Y) is 1:0.4-1.5; the temperature for the reaction between the intermediate product of step (1) and the compound represented by formula (Y) is 50-160°C; the time for the reaction between the intermediate product of step (1) and the compound represented by formula (Y) is 1-15h.

12. The method according to claim 7, characterized in that The compound represented by formula (X) is selected from the group consisting of (Z)-9-tetradecenoic acid pentyl ester, (Z)-9-tetradecenoic acid n-hexyl ester, (Z)-9-tetradecenoic acid isohexyl ester, (Z)-9-tetradecenoic acid n-octyl ester, (Z)-9-tetradecenoic acid isooctyl ester, (Z)-9-tetradecenoic acid 2-octyldodecyl ester, (Z)-9-tetradecenoic acid 2-decyl-1-tetradecyl ester, (Z)-9-tetradecenoic acid-2,2-dimethyl-1-propyl ester, (Z)- 9-tetradecenoic acid-2-ethyl-1-butyl ester, (Z)-9-hexadecenoic acid pentyl ester, (Z)-9-hexadecenoic acid n-hexyl ester, (Z)-9-hexadecenoic acid isohexyl ester, (Z)-9-hexadecenoic acid n-octyl ester, (Z)-9-hexadecenoic acid-2-ethylhexyl ester, (Z)-9-hexadecenoic acid-2-octyldodecyl ester, (Z)-9-hexadecenoic acid-2-decyl-1-tetradecyl ester, (Z)-9-hexadecenoic acid-2,2-dimethyl -1-propyl ester, (Z)-9-hexadecenoic acid-2-ethyl-1-butyl ester, oleic acid amyl ester, oleic acid n-hexyl ester, oleic acid isohexyl ester, oleic acid n-octyl ester, oleic acid-2-ethylhexyl ester, oleic acid-2-octyldodecyl ester, oleic acid-2-decyl-1-tetradecyl ester, oleic acid-2,2-dimethyl-1-propyl ester, oleic acid-2-ethyl-1-butyl ester, (Z)-13-docenoic acid amyl ester, (Z)-13-docenoic acid n-hexyl ester, (Z)- One or more of (Z)-13-docosenoic acid isohexyl ester, (Z)-13-docosenoic acid n-octyl ester, (Z)-13-docosenoic acid-2-ethylhexyl ester, (Z)-13-docosenoic acid-2-octyldodecyl ester, (Z)-13-docosenoic acid-2-decyl-1-tetradecyl ester, (Z)-13-docosenoic acid-2,2-dimethyl-1-propyl ester, and (Z)-13-docosenoic acid-2-ethyl-1-butyl ester; The compound represented by formula (Y) is selected from tert-octylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N,N'-bis(3-aminopropyl)-1,2-ethylenediamine, N,N'-bis(3-aminopropyl)-1,3-propylenediamine, 3,3'-diaminodipropylamine, 4-aminomorpholine, 3-methyl-4-aminomorpholine, 4-(2-aminomethyl)morpholine, 4-(2-aminoethyl)morpholine, 3-methyl-4-(2-aminoethyl)morpholine, N-(3-aminopropyl)morpholine, 4-morpholinebutylamine, 1,4-bis-(3-aminopropyl)piperazine, N -(3-aminopropyl)piperazine, 1,4-piperazinediethylamine, 1-(2-aminoethyl)piperazine, 2-methyl-1-(2-aminoethyl)piperazine, 1,4-piperazinedimethylamine, piperazine-1-methylamine, 1,4-diaminopiperazine, 2-methyl-1,4-piperazinediamine, thiomorpholine-4-methylamine, 4-(2-aminoethyl)thiomorpholine, 4-(3-aminopropyl)thiomorpholine, 2-(2-methylpiperazine-1-yl)-1-ethylamine, 2-methyl-2-(4-morpholine)propylamine, 2-(2-methylmorpholine-4-yl)ethane-1-amine or more.

13. The method according to claim 7, characterized in that The reaction of step (1) and / or step (2) is carried out under the protection of inert gas.

14. Use of the imide compound according to any one of claims 1 to 6 or the imide compound prepared by the method according to any one of claims 7 to 13 as a diesel antiwear agent.

15. A diesel composition comprising base diesel, the imide compound according to any one of claims 1 to 6 or the imide compound prepared by the method according to any one of claims 7 to 13.

16. The diesel composition according to claim 15, characterized in that The mass of the imide compound relative to the base diesel is 50-500 mg / kg.

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