An anti-oxidation and corrosion resistant soot dispersant, a preparation method and application thereof

Abstract

The present application relates to the technical field of engine oil, in particular to an anti-oxidation and anti-corrosion soot dispersant as well as a preparation method and application thereof; the preparation method comprises the following steps: carrying out ring-opening reaction on p-aminodiphenylamine and epoxypropanol to obtain a pre-amine; carrying out oxidative polymerization on the pre-amine and p-phenylenediamine under the action of an oxidant to obtain an aniline oligomer derivative; and carrying out reaction on the aniline oligomer derivative, polyethylene polyamine and polyisobutylene succinic anhydride to obtain the dispersant; the dispersant comprises a mixture of compounds represented by formula 1 to formula 3; the dispersant has excellent anti-metal corrosion performance by virtue of the aniline oligomer structure; the aniline oligomer contains multiple benzene ring structures, so that the dispersant has soot dispersibility and improves the overall performance of the composite agent; meanwhile, the product obtained after the reaction of the aniline oligomer and polyisobutylene succinic anhydride has good oil solubility, which brings a new idea for the application of the aniline oligomer in other oil-soluble corrosion prevention fields.

Description

Technical Field

[0001] This invention relates to the field of engine oil technology, specifically to an antioxidant and anti-corrosion soot dispersant, its preparation method, and its application. Background Technology

[0002] In recent years, NOx (nitrogen oxides) emissions from diesel engine exhaust have become increasingly stringent. To meet these standards, engine manufacturers have introduced technologies such as delayed injection, SCR (selective catalytic reduction), DPF (diesel particulate filter), and EGR (exhaust gas recirculation) to improve engines. These engine improvements have led to significant adjustments in engine oil formulations.

[0003] EGR increases the soot content in lubricating oil, which leads to a sharp increase in oil viscosity and causes wear on engine valve bearings and other components. Therefore, sufficient dispersants need to be added to address this issue. DPF requires the use of low-ash lubricating oil and low-sulfur fuel. Since low-sulfur fuel requires low-base-value oils, the dosage of detergents and ZDDP (zinc dialkyl dithiophosphate) is reduced. The reduction in ZDDP not only lowers ash content but also reduces the impact of phosphorus on the catalyst in the exhaust gas catalytic converter. The reduced detergent dosage needs to be compensated for by increasing the dispersant dosage. Conversely, the reduced ZDDP dosage needs to be compensated for by increasing the dosage of inhibitors (oxidation inhibitors, corrosion inhibitors, and wear inhibitors) to offset the performance loss caused by the reduced ZDDP. Comparative studies show that, compared to 1993, the dosage of dispersants in heavy-duty diesel engine oil formulations increased significantly in 2005, while the dosage of detergents and ZDDP decreased. Furthermore, the dosage of inhibitors, which can compensate for the performance deficiencies of ZDDP, also dropped sharply from 15.7% to 6.3%. Therefore, with limited dosages of various additives, developing multifunctional additives can effectively compensate for the performance losses caused by the reduction of some additives, thereby balancing the overall formulation and ensuring the oil meets the engine's operating requirements.

[0004] Some technological improvements implemented by engine manufacturers to meet environmental emission requirements have exacerbated the incomplete combustion of diesel fuel, leading to increased soot content in heavy-duty diesel engine oils. This causes a sharp increase in oil viscosity, resulting in a loss of protection for engine components and a series of problems such as wear. Therefore, dispersants are needed to prevent the aggregation and sedimentation of these soots, ensuring their stable dispersion in the lubricating oil and reducing the viscosity increase during use. Polyisobutylene succinimide ashless dispersant is a commonly used dispersant in lubricating oils, possessing good thermal stability, oxidation stability, and high-temperature dispersibility. It effectively disperses sludge and varnish formed during oil use due to oxidation, but its ability to disperse soot is very weak. "Mack T-11" bench tests revealed that even significantly increasing the dosage of traditional ashless dispersants cannot effectively control the increase in oil viscosity caused by increased soot. Therefore, a dispersant that can provide effective soot dispersion performance is needed. Current research on soot dispersants is increasingly trending towards multifunctionality. Improving the other application properties of dispersants to enhance their performance in composites and improve the overall performance of composites has become a research direction for soot dispersants.

[0005] ZDDP (zinc dialkyl dithiophosphate) is a low-cost, multifunctional additive with excellent antioxidant and anti-corrosion properties, as well as some anti-wear effects. However, with the application of technologies such as diesel particulate filters and exhaust catalytic converters, engine oils are required to be low in phosphorus and low in ash. Because ZDDP contains sulfur, phosphorus, and zinc, its application in automotive engine oils is significantly limited. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention aims to provide an antioxidant and corrosion smear dispersant, its preparation method and application, so as to solve the problem of the limited functionality of existing diesel engine oil dispersants.

[0007] The purpose of this invention is to prepare a novel ashless dispersant that combines antioxidant and corrosion resistance with excellent soot dispersibility. When applied to internal combustion engine lubricating oil, it can provide excellent soot dispersibility and, in conjunction with ZDDP, provide excellent antioxidant and corrosion resistance.

[0008] Using p-aminodiphenylamine, glycidol, and p-phenylenediamine as raw materials, p-aminodiphenylamine and glycidol were first subjected to a ring-opening reaction to obtain a pre-amine. Then, this pre-amine was oxidatively polymerized with p-phenylenediamine under the action of an oxidant to obtain an aniline oligomer derivative. Finally, this aniline oligomer derivative, polyethylene polyamine, and polyisobutylene succinic anhydride were reacted to obtain a novel dispersant.

[0009] To solve the above problems, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a method for preparing an antioxidant and corrosion-resistant soot dispersant, comprising:

[0011] The ring-opening reaction of p-aminodiphenylamine and glycidol yields a pre-prepared amine.

[0012] The pre-prepared amine and p-phenylenediamine were subjected to oxidative polymerization under the action of an oxidant to obtain an aniline oligomer derivative.

[0013] The aniline oligomer derivative, polyethylene polyamine, and polyisobutylene succinic anhydride were reacted to obtain a dispersant.

[0014] As one possible implementation, the ring-opening reaction of p-aminodiphenylamine and glycidol to obtain a pre-prepared amine includes:

[0015] At 0-50℃, an ethanol solution of glycidol is slowly added dropwise to an ethanol solution of p-aminodiphenylamine. After the addition is complete, the reaction continues for 2-10 hours. The ethanol is then evaporated to dryness to obtain the pre-prepared amine. The molar ratio of glycidol to p-aminodiphenylamine is 0.6:1-1.5:1.

[0016] More preferably, the ring-opening reaction of p-aminodiphenylamine and glycidol to obtain a pre-prepared amine comprises:

[0017] At 10-30℃, an ethanol solution of glycidol is slowly added dropwise to an ethanol solution of p-aminodiphenylamine. After the addition is complete, the reaction continues for 3-7 hours. The ethanol is then evaporated to dryness to obtain the pre-prepared amine. The molar ratio of glycidol to p-aminodiphenylamine is 0.8:1-1.1:1.

[0018] The dripping time is 1-4 hours, preferably 1.5-3 hours.

[0019] In one possible implementation, the volume of ethanol in the ethanol solution of glycidol is 1-5 times the mass of glycidol; and the volume of ethanol in the ethanol solution of p-aminodiphenylamine is 2-8 times the mass of p-aminodiphenylamine.

[0020] More preferably, the volume of ethanol in the ethanol solution of glycidol is 2-3 times the mass of glycidol; and the volume of ethanol in the ethanol solution of p-aminodiphenylamine is 3-5 times the mass of p-aminodiphenylamine.

[0021] As one possible implementation, the step of oxidatively polymerizing the pre-prepared amine with p-phenylenediamine under the action of an oxidant to obtain an aniline oligomer derivative includes:

[0022] Pre-formed amine and p-phenylenediamine were dissolved in DMF, and 40% phosphoric acid aqueous solution was added. At a temperature of 0-80℃, ammonium persulfate was added dropwise to the reaction system, and the reaction was continued for 0.5-3 hours. The reaction solution was added to water with a mass of 2-5 times that of DMF, stirred and filtered to obtain crude aniline oligomer derivative. The crude product was dissolved in DMF, filtered to remove inorganic salts, water was added to the filtrate to precipitate solid, and the solid was dried after filtration to obtain aniline oligomer.

[0023] The mass of DMF in which the pre-amine and p-phenylenediamine are dissolved is 2-8 times the total mass of the pre-amine and p-phenylenediamine; the molar ratio of phosphoric acid to p-phenylenediamine is 2.0-4.0:1; the molar ratio of ammonium sulfate to p-phenylenediamine is 1.5-3:1; and the molar ratio of pre-amine to p-phenylenediamine is 2.5:1 to 1.5:1.

[0024] More preferably, the step of oxidatively polymerizing the pre-prepared amine with p-phenylenediamine under the action of an oxidant to obtain an aniline oligomer derivative includes:

[0025] Pre-formed amine and p-phenylenediamine were dissolved in DMF, and 40% phosphoric acid aqueous solution was added. At a temperature of 15-30℃, ammonium persulfate was added dropwise to the reaction system, and the reaction was continued for 1-2 hours. The reaction solution was added to water with a mass of 2-5 times that of DMF, stirred and filtered to obtain crude aniline oligomer derivative. The crude product was dissolved in DMF, filtered to remove inorganic salts, water was added to the filtrate to precipitate solid, and the solid was dried after filtration to obtain aniline oligomer.

[0026] The mass of DMF in which the pre-amine and p-phenylenediamine are dissolved is 3-5 times the total mass of the pre-amine and p-phenylenediamine; the molar ratio of phosphoric acid to p-phenylenediamine is 2-3:1; the molar ratio of ammonium sulfate to p-phenylenediamine is 1.8-2.3:1; and the molar ratio of pre-amine to p-phenylenediamine is 2.2:1 to 1.8:1.

[0027] The ammonium persulfate is added to the reaction system dropwise over a period of 1-5 hours, preferably 1.5-3 hours.

[0028] As one possible implementation, the molar ratio of the aniline oligomer derivative to the polyethylene polyamine is 0.1-5:1; the molar ratio of the polyisobutylene succinic anhydride to the sum of the molar numbers of the aniline oligomer derivative and the polyethylene polyamine is 1.2-3:1.

[0029] More preferably, the molar ratio of the aniline oligomer derivative to the polyethylene polyamine is 0.25-2:1; and the molar ratio of the polyisobutylene succinic anhydride to the sum of the molar numbers of the aniline oligomer derivative and the polyethylene polyamine is 1.7-2.5:1.

[0030] As one possible implementation, the polyethylene polyamine is one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0031] Secondly, the present invention provides an antioxidant and corrosion-resistant soot dispersant prepared by the preparation method of the aforementioned antioxidant and corrosion-resistant soot dispersant.

[0032] One possible implementation includes a mixture of compounds with the structural formulas shown in Formulas 1-3;

[0033] Equation 1 is:

[0034]

[0035] Equation 2 is:

[0036]

[0037] Equation 3 is:

[0038]

[0039] Wherein, PIB is a polyisobutylene molecular chain, and x is an integer greater than or equal to 1; more preferably, x is an integer between 2 and 6.

[0040] Thirdly, the present invention provides the application of the antioxidant and corrosion-resistant soot dispersant in the preparation of diesel engine lubricating oil.

[0041] As one possible implementation, the diesel engine lubricating oil contains ZDDP.

[0042] The beneficial effects of this invention are as follows: This invention utilizes the aniline oligomer structure to endow the dispersant with excellent anti-metal corrosion properties. The aniline oligomer contains multiple benzene ring structures, which also makes this novel ashless dispersant have excellent soot dispersibility, exhibiting better application characteristics in internal combustion engine oil composites and improving the overall performance of the composites. At the same time, the product obtained by reacting the aniline oligomer with polyisobutylene succinic anhydride has good oil solubility, which brings new ideas for the application of aniline oligomers in other oil-soluble anti-corrosion fields. Attached Figure Description

[0043] Figure 1 This is a schematic diagram illustrating the preparation principle of the antioxidant and corrosion-resistant soot dispersant according to an embodiment of the present invention. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to specific embodiments.

[0045] It should be noted that these embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Simple improvements to the method under the premise of the present invention are all within the scope of protection claimed by the present invention.

[0046] like Figure 1 The reaction process shown illustrates a method for preparing an antioxidant and corrosion-resistant soot dispersant:

[0047] Synthesis of the pre-formulated amine: p-aminodiphenylamine is dissolved in a certain amount of ethanol (the volume of ethanol is 2 to 8 times the mass of p-aminodiphenylamine, preferably 3 to 5 times), and glycidol is dissolved in ethanol (the volume of ethanol is 1 to 5 times the mass of p-glycidol, preferably 2 to 3 times). At a temperature of 0 to 50°C (preferably 10 to 30°C), the ethanol solution of glycidol is slowly added dropwise to the ethanol solution of p-aminodiphenylamine while stirring (the molar ratio of glycidol to p-aminodiphenylamine is 0.6:1 to 1.5:1, preferably 0.8:1 to 1.1:1). The addition time is 1 to 4 hours (preferably 1.5 to 3 hours). After the addition is complete, the reaction is continued at a temperature of 0 to 50°C (preferably 10 to 30°C) for 2 to 10 hours (preferably 3 to 7 hours). After the reaction is completed, the ethanol is evaporated to dryness to obtain the pre-formulated amine.

[0048] Synthesis of oligomeric aniline derivatives: Pre-formed amine and p-phenylenediamine (molar ratio of pre-formed amine to p-phenylenediamine is 2.5:1 to 1.5:1, preferably 2.2:1 to 1.8:1) are dissolved in DMF (N,N-dimethylformamide) (the amount of DMF is 2 to 8 times the total mass of the two solids, preferably 3 to 5 times), and a certain amount of 40% phosphoric acid aqueous solution (molar ratio of phosphoric acid to p-phenylenediamine is 2.0 to 4.0:1, preferably 2.0 to 3.0:1) is added. At a temperature of 0 to 80°C (preferably 15 to 30°C), ammonium persulfate in a molar ratio of 1.5 to 3.0 times (preferably 1.8 to 2.3 times) of p-phenylenediamine is uniformly added to the reaction system over a certain time (1 to 5 h, preferably 1.5 to 3 h). After the ammonium persulfate is added, the reaction continues for 0.5 to 3 h (preferably 1 to 2 h). After the reaction is complete, the reaction solution is added to water at a mass of 2 to 5 times that of DMF. After thorough stirring, the mixture is filtered to obtain a crude product of aniline oligomer derivative. The crude product is then dissolved in DMF again, filtered to remove inorganic salts, and water is added to the filtrate to precipitate solids. After filtration, the solid particles are dried to obtain aniline oligomers.

[0049] Synthesis of dispersant: The obtained aniline oligomer and polyethylene polyamine (molar ratio 0.1-5:1, preferably 0.25-2:1) are subjected to a dehydration reaction with polyisobutylene succinic anhydride at a certain temperature (70-250℃, preferably 140-230℃) to obtain a dispersant product containing aniline oligomer structure.

[0050] The selected polyisobutylene succinic anhydride is synthesized using a commonly used method in the industry, namely, polyisobutylene (number average molecular weight 500-5000, preferably 1300-2500) and maleic anhydride through a thermal addition process or a free radical process. The polyethylene polyamine includes, but is not limited to, one or more mixtures of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. The molar ratio of polyisobutylene succinic anhydride to the total molar ratio of aniline oligomer and polyethylene polyamine is 1.2-3.0:1, preferably 1.7-2.5:1.

[0051] Example 1:

[0052] 55.3 g of p-aminodiphenylamine was dissolved in 170 ml of ethanol in a reaction flask. After stirring and dissolving, the reaction flask was placed in an ice-water bath and the temperature was stabilized at 10 °C. 17.4 g of glycidol was dissolved in 40 ml of ethanol and added dropwise to the reaction flask over 2.5 h. During the addition, the temperature inside the reaction flask was controlled at 10–20 °C. After the addition was completed, the reaction was continued at 10–20 °C for 5 h. After the reaction was completed, the ethanol was removed by rotary evaporation to obtain a solid pre-amine.

[0053] Add 48.5 g of the pre-prepared amine, 10.8 g of p-phenylenediamine, and 180 g of DMF to a reaction flask, stir to dissolve, then add 54 g of 40% phosphoric acid aqueous solution. Place the reaction flask in an ice-water bath and stabilize the temperature at 15°C. Over 2 hours, uniformly add 45.6 g of ammonium persulfate to the reaction flask, controlling the temperature inside the flask at 15–25°C. After the addition is complete, maintain the temperature at 15–25°C and continue the reaction for another 2 hours. After the reaction is complete, add the solution to 450 g of water, stir thoroughly, and filter. Dissolve the obtained solid again in DMF, filter, add water to the filtrate, filter out the precipitated solid, and dry it to obtain the aniline oligomer.

[0054] Example 2

[0055] 55.3 g of p-aminodiphenylamine was dissolved in 140 ml of ethanol in a reaction flask. After stirring and dissolving, the reaction flask was placed in an ice-water bath and the temperature was stabilized at 5 °C. 20.9 g of glycidol was dissolved in 60 ml of ethanol and added dropwise to the reaction flask over 3.5 h. During the addition, the temperature inside the reaction flask was controlled at 5–15 °C. After the addition was completed, the reaction was continued at 5–15 °C for 8 h. After the reaction was completed, the ethanol was removed by rotary evaporation to obtain a solid pre-amine.

[0056] Add 36.5 g of the pre-prepared amine, 10.8 g of p-phenylenediamine, and 200 g of DMF to a reaction flask, stir to dissolve, then add 73.5 g of 40% phosphoric acid aqueous solution. Place the reaction flask in an ice-water bath and stabilize the temperature at 25°C. Over 3 hours, add 37.0 g of ammonium persulfate evenly to the reaction flask, controlling the temperature inside the flask at 25–35°C. After the addition is complete, maintain the temperature at 25–35°C and continue the reaction for 1 hour. After the reaction is complete, add the solution to 600 g of water, stir thoroughly, and filter. Dissolve the obtained solid again in DMF, filter, add water to the filtrate, filter out the precipitated solid, and dry it to obtain the aniline oligomer.

[0057] Example 3

[0058] 55.3 g of p-aminodiphenylamine was dissolved in 220 ml of ethanol in a reaction flask. After stirring and dissolving, the reaction flask was placed in an ice-water bath and the temperature was stabilized at 15 °C. 13.9 g of glycidol was dissolved in 15 ml of ethanol and added dropwise to the reaction flask over 4.0 h. During the addition, the temperature inside the reaction flask was controlled at 15–25 °C. After the addition was completed, the reaction was continued at 15–25 °C for 2.5 h. After the reaction was completed, the ethanol was removed by rotary evaporation to obtain a solid pre-amine.

[0059] Add 60.5 g of the pre-prepared amine, 10.8 g of p-phenylenediamine, and 180 g of DMF to a reaction flask, stir to dissolve, then add 49 g of 40% phosphoric acid aqueous solution. Place the reaction flask in an ice-water bath and stabilize the temperature at 30°C. Over 4 hours, uniformly add 52.5 g of ammonium persulfate to the reaction flask, controlling the temperature inside the flask at 30–40°C. After the addition is complete, maintain the temperature at 30–40°C and continue the reaction for another 0.5 hours. After the reaction is complete, add the solution to 400 g of water, stir thoroughly, and filter. Dissolve the obtained solid again in DMF, filter, add water to the filtrate, filter out the precipitated solid, and dry it to obtain the aniline oligomer.

[0060] Example 4

[0061] 2300 g (1.0 mol) of highly reactive polyisobutylene (number average molecular weight 2300, α-olefin content ≥85 wt%) was added to a 5000 ml stainless steel high-pressure reactor. Nitrogen gas was purged, and the mixture was stirred and heated to 200 °C. 176.5 g (1.8 mol) of molten maleic anhydride was slowly added dropwise over 30 min using a dropping device. After the addition was complete, the temperature inside the reactor was slowly raised to 230 °C, and the reaction was continued at this temperature for 4 hours. After the reaction, nitrogen gas was blown into the reactor to expel any unreacted maleic anhydride. The saponification value of the reaction product was measured to be 60 mg KOH / g.

[0062] Example 5

[0063] Add 150g of the reaction product from Example 4 and 107.7g of 150N hydrogenated base oil to a 500ml four-necked flask, stir and heat to 70-80°C, add 7.9g of aniline oligomer from Example 1 and 5.1g of tetraethylenepentamine, then slowly heat the material to 175°C, purge the reaction with nitrogen gas for 4 hours, remove the water produced by the reaction, and then filter under positive pressure to obtain the reaction product.

[0064] Example 6

[0065] Add 150g of the reaction product from Example 4 and 108.2g of 150N hydrogenated base oil to a 500ml four-necked flask, stir and heat to 70-80°C, add 10.3g of aniline oligomer from Example 1 and 3.3g of tetraethylenepentamine, then slowly heat the material to 185°C, purge the reaction with nitrogen gas for 3 hours, remove the water produced by the reaction, and then filter under positive pressure to obtain the reaction product.

[0066] Example 7

[0067] Add 150g of the reaction product from Example 4 and 109.1g of 150N hydrogenated base oil to a 500ml four-necked flask, stir and heat to 70-80°C, add 7.32g of aniline oligomer from Example 2 and 7.79g of tetraethylenepentamine, then slowly heat the material to 160°C, purge the reaction with nitrogen gas for 5 hours, remove the water produced by the reaction, and then filter under positive pressure to obtain the reaction product.

[0068] Example 8

[0069] Add 150g of the reaction product from Example 4 and 108.3g of 150N hydrogenated base oil to a 500ml four-necked flask, stir and heat to 70-80°C, add 11.41g of aniline oligomer from Example 3 and 2.43g of tetraethylenepentamine, then slowly heat the material to 200°C, purge the reaction with nitrogen gas for 2.5h, remove the water produced by the reaction, and then filter under positive pressure to obtain the reaction product.

[0070] Comparative Example 1

[0071] Add 150 g of the polyisobutylene succinic anhydride prepared in Example 4 and 104.10 g of 150N hydrogenated base oil to a 500 ml four-necked flask. Slowly heat to 70–80 °C and stir until homogeneous. Then add 7.6 g of tetraethylenepentamine. After the addition is complete, slowly heat the material to 150–170 °C and purge the reaction with nitrogen for 4 hours. Remove the water produced in the reaction and then filter under positive pressure to obtain the reaction product.

[0072] The dispersants obtained in Examples 5-8 and Comparative Example 1 were added to the used engine test oil at dosages of 0.5 wt% and 1.0 wt%, respectively. The soot content of the oil was 5.9 wt% according to TGA analysis, and the kinematic viscosity at 100°C was 60.38 mm² / s. After stirring the used oil with added dispersant at 100°C for 2 hours, the kinematic viscosity at 100°C was measured and the viscosity reduction rate was calculated. The lower the kinematic viscosity and the greater the viscosity reduction rate, the stronger the ability of the added dispersant to prevent the oil from thickening. The results are shown in Table 1.

[0073] Table 1. Dispersant test results obtained in Examples 5-8 and Comparative Example 1

[0074]

[0075]

[0076] According to the dispersibility evaluation data in Table 1, the novel antioxidant and corrosion-resistant soot dispersant prepared in this patent example has a significantly better inhibitory effect on thickening of old oil than the traditional polyisobutylene succinimide (Comparative Example 1) at the same dosage. At the same time, comparing the viscosity reduction rate of old oil with different dosages, it can be seen that increasing the dosage of traditional polyisobutylene succinimide has a relatively small inhibitory effect on the viscosity increase of oil caused by soot, while the novel antioxidant and corrosion-resistant soot dispersant prepared in this patent example can effectively reduce the viscosity increase of oil caused by soot.

[0077] The dispersants obtained in Examples 5-8 and Comparative Example 1 were added to the same default oil at the same dosage (5.0 wt%) to prepare 15W / 40 viscosity grade diesel engine oils, which were then subjected to HTCBT (High Temperature Corrosion Bench Test) according to the ASTM D6594 standard procedure. The lower the copper content in the oil, the better its corrosion resistance. As shown in the table above, compared with the traditional ashless dispersant (Comparative Example 1), the novel antioxidant and corrosion-resistant soot dispersant prepared in this patent example has excellent antioxidant and corrosion-resistant properties. A comparison with traditional dispersants demonstrates that the dispersant in this patent application, when combined with ZDDP, exhibits excellent corrosion resistance.

[0078] High molecular weight polyaniline, due to its poor solubility and infusibility, has significant limitations in processing and application. In contrast, low molecular weight aniline oligomers exhibit good solubility and processability. Although their degree of polymerization is lower, aniline oligomers still possess various properties of high molecular weight polyaniline, such as the ability to adsorb onto metal surfaces and form a protective film, thereby inhibiting corrosion of metal parts. This patent utilizes the structure of aniline oligomers to endow this dispersant with excellent anti-metal corrosion properties. The presence of multiple benzene ring structures in aniline oligomers also gives this novel ashless dispersant excellent soot dispersibility, demonstrating better application characteristics in internal combustion engine oil composites and improving the overall performance of the composite. Furthermore, the product obtained by reacting this aniline oligomer with polyisobutylene succinic anhydride has good oil solubility, providing new insights for the application of aniline oligomers in other oil-soluble corrosion protection fields.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described with reference to preferred embodiments, those skilled in the art should understand that various changes in form and detail can be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for preparing an antioxidant and corrosion-resistant soot dispersant, characterized in that, include: The ring-opening reaction of p-aminodiphenylamine and glycidol yields a pre-prepared amine. The pre-prepared amine and p-phenylenediamine were subjected to oxidative polymerization under the action of an oxidant to obtain an aniline oligomer derivative. The aniline oligomer derivative, polyethylene polyamine, and polyisobutylene succinic anhydride were reacted to obtain a dispersant.

2. The preparation method of the antioxidant and corrosion-resistant soot dispersant as described in claim 1, characterized in that, The step of reacting p-aminodiphenylamine and glycidol in a ring-opening reaction to obtain a pre-prepared amine includes: At 0-50℃, an ethanol solution of glycidol is slowly added dropwise to an ethanol solution of p-aminodiphenylamine. After the addition is complete, the reaction continues for 2-10 hours. The ethanol is then evaporated to dryness to obtain the pre-prepared amine. The molar ratio of glycidol to p-aminodiphenylamine is 0.6:1-1.5:

1.

3. The preparation method of the antioxidant and corrosion-resistant soot dispersant as described in claim 2, characterized in that, The volume of ethanol in the ethanol solution of glycidol is 1-5 times the mass of glycidol; the volume of ethanol in the ethanol solution of p-aminodiphenylamine is 2-8 times the mass of p-aminodiphenylamine.

4. The preparation method of the antioxidant and anti-corrosion soot dispersant as described in claim 3, characterized in that, The step of oxidatively polymerizing the pre-prepared amine with p-phenylenediamine under the action of an oxidant to obtain an aniline oligomer derivative includes: Pre-formed amine and p-phenylenediamine were dissolved in DMF, and 40% phosphoric acid aqueous solution was added. Ammonium persulfate was added dropwise to the reaction system at 0-80℃, and the reaction was continued for 0.5-3 hours. The reaction solution was added to water with a mass of 2-5 times that of DMF, stirred and filtered to obtain crude aniline oligomer derivative. The crude product was dissolved in DMF, filtered to remove inorganic salts, water was added to the filtrate to precipitate solid, and the solid was dried after filtration to obtain aniline oligomer. The mass of DMF in which the pre-amine and p-phenylenediamine are dissolved is 2-8 times the total mass of the pre-amine and p-phenylenediamine; the molar ratio of phosphoric acid to p-phenylenediamine is 2.0-4.0:1; the molar ratio of ammonium sulfate to p-phenylenediamine is 1.5-3:1; and the molar ratio of pre-amine to p-phenylenediamine is 2.5:1 to 1.5:

1.

5. The preparation method of the antioxidant and anti-corrosion soot dispersant as described in claim 4, characterized in that, The molar ratio of the aniline oligomer derivative to the polyethylene polyamine is 0.1-5:1; the molar ratio of the polyisobutylene succinic anhydride to the sum of the molar numbers of the aniline oligomer derivative and the polyethylene polyamine is 1.2-3:

1.

6. The preparation method of the antioxidant and anti-corrosion soot dispersant as described in claim 5, characterized in that, The polyethylene polyamine is one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

7. An antioxidant and corrosion-resistant soot dispersant prepared by the preparation method of any one of claims 1-6.

8. The antioxidant and anti-corrosion soot dispersant as described in claim 7, characterized in that, Includes mixtures of compounds with the structural formulas shown in Formulas 1-3; Equation 1 is: Equation 2 is: Equation 3 is: Wherein, PIB is a polyisobutylene molecular chain, and x is an integer greater than or equal to 1.

9. The application of the antioxidant and corrosion-resistant soot dispersant according to claim 7 or 8 in the preparation of diesel engine lubricating oil.

10. The application of the antioxidant and anti-corrosion soot dispersant as described in claim 9 in the preparation of diesel engine lubricating oil, characterized in that, The diesel engine lubricating oil contains ZDDP.

Images