A soot dispersing polyisobutylene succinimide dispersant, its preparation method and application

Abstract

This invention belongs to the field of lubricating oil additives, specifically relating to a soot-dispersible polyisobutylene succinimide dispersant, its preparation method, and its application. The preparation method includes the following steps: (1) mixing polyisobutylene maleic anhydride, base oil, and aromatic solvent, stirring evenly, heating, adding polyethylene polyamine, introducing nitrogen gas, heating to the aromatic reflux temperature, and performing an amidation reaction to obtain product 1; (2) adding aminophenylboronic acid to product 1, continuing reflux, borizing reaction, removing the solvent by vacuum distillation, filtering, and obtaining the soot-dispersible polyisobutylene succinimide dispersant. The dispersant in this invention has the characteristic of good soot dispersion performance. The prepared product can improve the soot dispersion of oil products with a lower dosage. Moreover, the use of aminophenylboronic acid for borization reaction can improve high-temperature detergency. The preparation process of this invention is simple and easy to implement.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil additives, specifically relating to a soot-dispersible polyisobutylene succinimide dispersant, its preparation method, and its application. Background Technology

[0002] Polyisobutylene succinimide is an important additive in lubricating oils, typically accounting for 20%-50% of diesel engine oil additives. Its preparation methods mainly include hydrocarbonation and amination processes: (1) Hydrocarbonation: Polyisobutylene reacts with maleic anhydride to generate polyisobutylene maleic anhydride; (2) Amination: Polyisobutylene maleic anhydride reacts with polar polyethylene polyamines (usually diethylenetriamine, triethylenetetramine, tetraethylenepentamine, etc.) to obtain polyisobutylene succinimide. Since its successful development, polyisobutylene succinimide dispersant has become the most widely used additive in internal combustion engine lubricating oil additives. However, the soot dispersion energy of polyisobutylene succinimide is insufficient, making improving its soot dispersion performance a research hotspot.

[0003] With advancements in automotive engine technology, there is a growing demand for lubricating oils with superior soot dispersibility. This is especially true for diesel engine oils of CI-4 and higher grades, which utilize exhaust gas recirculation (EGR) technology. While EGR effectively reduces nitrogen oxide emissions, it also increases soot formation in the engine lubricating oil. Soot primarily forms near the cylinder walls and easily enters the engine's lubrication system with the flow of gasoline engine oil. As the engine runs, the soot concentration gradually increases, rapidly increasing the kinematic viscosity of the oil, reducing its fluidity. Accumulated soot particles can also clog filters, exacerbating engine wear. Polyisobutylene succinimide (POS), with its soot dispersing properties, has become a key additive for addressing the soot dispersion problem in engine oils.

[0004] US Patent Application US08324139B2 discloses the use of aminodiphenylamine and indigo anhydride in a 1:1 ratio, and the product is then reacted with polyisobutylene maleic anhydride to obtain a polyisobutylene succinimide product with good soot dispersibility, which can effectively solve the problem of lubricant viscosity increase caused by soot.

[0005] US Patent Application US08067347B2 discloses a method for preparing polyisobutylene succinimide by reacting a mixture of various polyetheramines and their derivatives, such as polyetheramine alcohol, polyalkylene polyamine, and N-phenylphenyldiamine, with polyisobutylene maleic anhydride. The resulting polyisobutylene succinimide product exhibits good soot dispersibility and can be used to blend high-grade diesel engine oils.

[0006] US Patent Application US08581006B2 discloses a method of reacting polyisobutylene maleic anhydride with glycerol, followed by a reaction with 4-aminodiphenylamine, to prepare a dispersant containing both polyisobutylene succinate and polyisobutylene succinimide. This dispersant can improve the soot dispersion performance of oil products.

[0007] US Patent Application US08877694B2 discloses that introducing heteroatom cyclic compounds such as imidazole and pyrimidine into the molecular structure of polyisobutylene succinimide can also effectively improve the soot dispersion performance of oil products.

[0008] Another frequently reported method involves grafting maleic anhydride onto high molecular weight compounds such as ethylene-propylene copolymers and poly-α-olefins, and then reacting them with polyethylene polyamines, 4-aminodiphenylamine, etc., to prepare high molecular weight products with good soot dispersibility.

[0009] The above-mentioned soot-dispersible polyisobutylene succinimide dispersants mainly suffer from problems such as complex synthesis processes, large dosage, and poor high-temperature cleaning performance. High-efficiency and multifunctional soot-dispersible additives have become an important research topic in high-grade diesel engine oil additives. Summary of the Invention

[0010] To address the shortcomings of existing technologies, this invention provides a soot-dispersible polyisobutylene succinimide dispersant and its preparation method. This invention uses polyisobutylene macklei anhydride to react with polyethylene polyamine to prepare polyisobutylene succinimide, and then reacts it with aminophenylboronic acid to prepare the soot-dispersible polyisobutylene succinimide. The soot-dispersible polyisobutylene succinimide prepared by this method has advantages such as simple synthesis process, good soot dispersion performance, low dosage, and good high-temperature detergency.

[0011] To achieve the above-mentioned objectives of this invention, the specific technical solution adopted by this invention is as follows:

[0012] A method for preparing a soot-dispersible polyisobutylene succinimide dispersant includes the following steps:

[0013] (1) Mix polyisobutylene maleic anhydride, base oil and aromatic solvent, stir evenly, heat up, add polyamine, purge with nitrogen, heat to the aromatic reflux temperature, carry out amidation reaction, and obtain product 1.

[0014] (2) Add aminophenylboronic acid to product 1, continue reflux, borate reaction, remove solvent by vacuum distillation, filter, and obtain the soot-dispersible polyisobutylene succinimide dispersant.

[0015] Preferably, the polyisobutylene maleic anhydride has a number-average molecular weight of 500-5000, more preferably 900-2500. The polyisobutylene maleic anhydride can be produced by a chlorination process, a thermal addition process, or a mixture of the two processes.

[0016] Preferably, the base oil has a kinematic viscosity of 2 mm at 100°C. 2 / s-20mm 2 / s, preferably 4mm 2 / s-8mm 2 / s.

[0017] Preferably, the aromatic solvent is selected from one or more of benzene, toluene, and xylene, with xylene being the most preferred.

[0018] Preferably, the polyamine is selected from one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine and polyethylene polyamine, and is preferably tetraethylenepentamine or polyethylene polyamine.

[0019] Preferably, the mass ratio of the polyisobutylene maleic anhydride, base oil, and aromatic solvent is 1:0.2-1:0.3-2, and more preferably 1:0.3-1:0.4-1.

[0020] Preferably, the molar ratio of the polyethylene polyamine to the polyisobutylene maleic anhydride is 1:1-3, more preferably 1:1.1-2.

[0021] Preferably, the stirring temperature in step (1) is 50-70°C, and the temperature is raised to 100-120°C. The amidation reaction time is 2-10 hours, preferably 6-8 hours.

[0022] Preferably, the aminophenylboronic acid in step (2) is selected from one or more of 2-aminophenylboronic acid, 3-aminophenylboronic acid and 4-aminophenylboronic acid.

[0023] Preferably, the molar ratio of aminophenylboronic acid to polyisobutylene maleic anhydride is 1:1-2, more preferably 1:1.1-1.5.

[0024] Preferably, the borylation reaction in step (2) takes 4-12 hours, more preferably 6-10 hours.

[0025] The present invention also relates to a soot-dispersible polyisobutylene succinimide dispersant prepared by the above preparation method.

[0026] This invention also relates to the application of the soot-dispersible polyisobutylene succinimide dispersant prepared by the above-mentioned method in the preparation of lubricating oil additives.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention utilizes the reaction of polyisobutylene macrenic acid anhydride with polyethylene polyamine to prepare polyisobutylene succinimide, which is then reacted with aminophenylboronic acid to prepare soot-dispersible polyisobutylene succinimide. This molecular structure contains not only aromatic rings but also oxygen-containing phenylboronic acid groups. Both the aromatic rings and phenylboronic acid groups exhibit good adsorption effects with soot particles, enhancing the soot dispersion ability of polyisobutylene succinimide. Furthermore, research has shown that this structure also possesses excellent high-temperature detergency properties. The prepared product can improve the soot dispersibility of oils with a relatively low dosage, and the preparation process of this invention is simple and easy to implement. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are not intended to limit the present invention, but only to illustrate the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are generally performed under conventional conditions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0030] Example 1

[0031] A method for preparing a soot-dispersible polyisobutylene succinimide dispersant:

[0032] (1) Add 100 parts (0.090 mol) of polyisobutylene maleic anhydride produced by thermal addition with a number-average molecular weight of 1112 to the reactor, and add 80 parts of a solution with a kinematic viscosity of 5.371 mm at 100℃. 2 The base oil (Group II mineral oil) was mixed with 50 parts xylene. The mixture was kept at 60°C and stirred at 180 rpm for 1 hour. The temperature was then raised to 100°C, and 11.5 parts (0.061 mol) of tetraethylenepentamine were added dropwise. After the addition was complete, nitrogen gas was introduced, and the temperature was raised to reflux temperature for amidation reaction for 6 hours to obtain intermediate product 1 (polyisobutylene succinimide). The nitrogen content of this product was 2.13%.

[0033] (2) 9.8 parts (0.072 mol) of 2-aminophenylboronic acid were added to the reactor and refluxed for 10 hours. The solvent was removed under reduced pressure and filtered to obtain soot-dispersed polyisobutylene succinimide with a nitrogen content of 2.36% and a boron content of 0.35%.

[0034] The structure of the main components of the soot-dispersible polyisobutylene succinimide dispersant is shown below:

[0035]

[0036] Example 2

[0037] A method for preparing a soot-dispersible polyisobutylene succinimide dispersant differs from Example 1 only in step (2), specifically as follows:

[0038] (2) 9.8 parts (0.072 mol) of 3-aminophenylboronic acid were added to the reactor and refluxed for 10 hours. The solvent was removed under reduced pressure and filtered to obtain soot-dispersed polyisobutylene succinimide with a nitrogen content of 2.41% and a boron content of 0.36%.

[0039] Example 3

[0040] A method for preparing a soot-dispersible polyisobutylene succinimide dispersant differs from Example 1 only in step (2), specifically as follows:

[0041] (2) 9.8 parts (0.072 mol) of 4-aminophenylboronic acid were added to the reactor and refluxed for 10 hours. The solvent was removed under reduced pressure and filtered to obtain soot-dispersed polyisobutylene succinimide with a nitrogen content of 2.41% and a boron content of 0.36%.

[0042] Example 4

[0043] A method for preparing a soot-dispersible polyisobutylene succinimide dispersant:

[0044] (1) Add 100 parts (0.071 mol) of polyisobutylene maleic anhydride produced by thermal addition with a number-average molecular weight of 1403 to the reactor, and add 80 parts of a solution with a kinematic viscosity of 6.171 mm at 100℃. 2 / s base oil (Group II mineral oil), 50 parts xylene, constant temperature to 60℃, stirred at 180 rpm for 1 h, then heated to 110℃, 6.74 parts (0.036 mol) of tetraethylenepentamine were added dropwise. After the addition was complete, nitrogen gas was introduced, and the temperature was raised to reflux temperature for amidation reaction for 6 hours to obtain the intermediate product 2 polyisobutylene succinimide. The nitrogen content of this product was 1.31%.

[0045] (2) 8.87 parts (0.065 mol) of 4-aminophenylboronic acid were added to the reactor and refluxed for 10 hours. The solvent was removed under reduced pressure and filtered to obtain soot-dispersed polyisobutylene succinimide with a nitrogen content of 1.68% and a boron content of 0.31%.

[0046] Example 5

[0047] A method for preparing a soot-dispersible polyisobutylene succinimide dispersant differs from Example 4 only in step (2), specifically as follows:

[0048] (2) 6.51 parts (0.048 mol) of 4-aminophenylboronic acid were added to the reactor and refluxed for 10 hours. The solvent was removed under reduced pressure and filtered to obtain soot-dispersed polyisobutylene succinimide with a nitrogen content of 1.56% and a boron content of 0.23%.

[0049] Example 6

[0050] A method for preparing a soot-dispersible polyisobutylene succinimide dispersant differs from Example 4 only in step (2), specifically as follows:

[0051] (2) 8.87 parts (0.065 mol) of 2-aminophenylboronic acid were added to the reactor and refluxed for 10 hours. The solvent was removed under reduced pressure and filtered to obtain soot-dispersed polyisobutylene succinimide with a nitrogen content of 1.69% and a boron content of 0.32%.

[0052] Example 7

[0053] A method for preparing a soot-dispersible polyisobutylene succinimide dispersant:

[0054] (1) Add 100 parts (0.046 mol) of polyisobutylene maleic anhydride produced by the chlorination process with a number average molecular weight of 2189 to the reactor, and add 80 parts of a solution with a kinematic viscosity of 4.216 mm at 100°C. 2 The base oil (Group II mineral oil) was mixed with 80 parts xylene. The mixture was kept at 60°C and stirred at 180 rpm for 1 hour. The temperature was then raised to 110°C, and 6.74 parts (0.036 mol) of tetraethylenepentamine were added dropwise. After the addition was complete, nitrogen gas was introduced, and the temperature was raised to reflux temperature for amidation reaction for 6 hours to obtain the intermediate product 3-polyisobutylene succinimide. The nitrogen content of this product was 1.35%.

[0055] (2) 5.62 parts (0.041 mol) of 4-aminophenylboronic acid were added to the reactor and refluxed for 10 hours. The solvent was removed under reduced pressure and filtered to obtain soot-dispersed polyisobutylene succinimide with a nitrogen content of 1.61% and a boron content of 0.22%.

[0056] Example 8

[0057] A method for preparing a soot-dispersible polyisobutylene succinimide dispersant differs from Example 7 only in step (2), specifically as follows:

[0058] (2) 5.62 parts (0.041 mol) of 2-aminophenylboronic acid were added to the reactor and refluxed for 6 hours. The solvent was removed under reduced pressure and filtered to obtain soot-dispersed polyisobutylene succinimide with a nitrogen content of 1.57% and a boron content of 0.21%.

[0059] Comparative Example 1

[0060] A method for preparing a polyisobutylene succinimide dispersant differs from Example 1 only in that the reaction in step (2) is not performed, and product 1 is finally obtained.

[0061] Comparative Example 2

[0062] A method for preparing a polyisobutylene succinimide dispersant differs from Example 4 only in that the reaction in step (2) is not performed, and product 2 is finally obtained.

[0063] Comparative Example 3

[0064] A method for preparing a polyisobutylene succinimide dispersant differs from Example 7 only in that the reaction in step (2) is not performed, and product 3 is finally obtained.

[0065] Comparative Example 4

[0066] A method for preparing a polyisobutylene succinimide dispersant differs from Example 1 only in step (2), specifically as follows:

[0067] (2) Add 4.40 parts (0.071 mol) of boric acid to the reaction vessel, continue to reflux, react for 10 hours, remove the solvent under reduced pressure, filter to obtain boronized polyisobutylene succinimide with a nitrogen content of 2.09% and a boron content of 0.38%.

[0068] Effect test

[0069] Test Example 1: Soot Dispersion Test

[0070] The soot dispersibility of diesel engine oil was evaluated using a diesel soot dispersibility tester. The evaluation method involved mixing a dispersant with diesel engine oil and placing it in a steel pipe, which served as the soot absorption tube. This pipe was then placed in a 100°C oil bath at a constant temperature. Soot produced after diesel combustion was drawn into the absorption tube. Over time, the soot content in the tube gradually increased, the viscosity of the oil increased, and the negative pressure in the tube slowly rose. The absorption time was recorded when the negative pressure reached -1200 Pa. A longer absorption time indicates a stronger soot-carrying capacity and better soot dispersibility.

[0071] The preparation method of the diesel engine oil is as follows: by weight, 3.0 parts of polyisobutylene succinimide dispersant, 0.3 parts of polyalphaolefin pour point depressant, 5.0 parts of polyethylene propylene copolymer viscosity index improver, 2.5 parts of magnesium alkyl sulfonate metal detergent, 0.8 parts of sulfurized alkylphenol calcium metal detergent, 0.7 parts of thiophosphoric bisoctyl zinc salt antioxidant and corrosion inhibitor, 0.3 parts of alkyl dithiocarbamate, 1.0 part of amine antioxidant and 86.4 parts of Group III mineral base oil are mixed evenly to obtain the product.

[0072] The products from Examples 1-8 and four comparative products were blended at a concentration of 3% each to form diesel engine oils, and their soot dispersion performance was tested. The test results are shown in Table 1.

[0073] Table 1 Results of soot dispersibility test

[0074] Sample Name Absorption time Example 1 5 hours and 29 minutes Example 2 5 hours and 37 minutes Example 3 5 hours and 28 minutes Example 4 5 hours and 39 minutes Example 5 5 hours and 31 minutes Example 6 5 hours and 48 minutes Example 7 6 hours 12 minutes Example 8 6 hours and 7 minutes Comparative Example 1 3 hours and 37 minutes Comparative Example 2 3 hours and 9 minutes Comparative Example 3 3 hours and 52 minutes Comparative Example 4 3 hours and 18 minutes

[0075] As shown in Table 1, the absorption time of the diesel engine oils blended in Comparative Examples 1-4 was less than 4 hours, while the absorption time of the diesel engine oils blended in Examples 1-8 was greater than 5 hours, indicating that the products of these examples have better soot dispersion. This demonstrates that introducing aminophenylboronic acid into the molecular structure of polyisobutylene succinimide effectively improves the soot dispersion performance of the product. It can also be seen that 2-aminophenylboronic acid, 3-aminophenylboronic acid, and 4-aminophenylboronic acid all have an effect on improving the soot dispersion performance of the product, with the three aminophenylboronic acids showing comparable improvement effects. Furthermore, as shown in Comparative Example 4, using borate-boronized polyisobutylene succinimide does not improve the soot dispersion performance of the additive.

[0076] The soot dispersion performance of diesel engine oil was evaluated when Example 8 was formulated with an addition of 2.5%. The absorption time was 4 hours and 56 minutes, indicating that even after reducing the dosage, it still had good soot dispersion.

[0077] Test Example 2: High Temperature Cleanliness Test

[0078] The high-temperature detergency performance was evaluated using an L-1 type plate coking tendency tester. The evaluation method was as follows: the test oil was heated to 100°C and splashed onto a 300°C test aluminum plate by a high-speed rotating oil splasher. After running for 2 hours, the weight of coke generated on the aluminum plate by the test oil sample was weighed to evaluate the high-temperature detergency. The smaller the amount of coke, the better the high-temperature detergency.

[0079] The products from Examples 1-8 and Comparative Examples 1-4 were blended at a 3% addition amount to form diesel engine oil (the preparation method of the diesel engine oil is the same as that of Test Example 1), and high-temperature detergency performance was tested. The results are shown in Table 2.

[0080] Table 2 Results of High-Temperature Cleanliness Test

[0081] Sample Name Coking amount per coke plate, mg Example 1 16.2 Example 2 15.7 Example 3 15.2 Example 4 14.7 Example 5 14.8 Example 6 15.1 Example 7 11.3 Example 8 11.9 Comparative Example 1 47.9 Comparative Example 2 25.8 Comparative Example 3 21.4 Comparative Example 4 16.3

[0082] As shown in Table 2, the coking amount of the products in the examples was less than 20 mg, exhibiting better high-temperature detergency compared to Comparative Examples 1-3. This indicates that introducing aminophenylboronic acid into the molecular structure of polyisobutylene succinimide can effectively improve high-temperature detergency. It can also be seen that the use of 2-aminophenylboronic acid, 3-aminophenylboronic acid, and 4-aminophenylboronic acid all significantly improved the high-temperature detergency of the products. Compared to Comparative Example 4, the high-temperature detergency performance evaluation results were comparable, indicating that the use of aminophenylboronic acid can achieve the same effect as using boric acid in improving the high-temperature detergency of the product.

[0083] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a soot-dispersible polyisobutylene succinimide dispersant, characterized in that, Includes the following steps: (1) Mix polyisobutylene maleic anhydride, base oil and aromatic solvent, stir evenly, heat up, add polyamine, purge with nitrogen, heat to the aromatic reflux temperature, carry out amidation reaction, and obtain product 1. (2) Add aminophenylboronic acid to product 1, continue reflux, borate reaction, remove solvent by vacuum distillation, filter, and obtain the soot-dispersible polyisobutylene succinimide dispersant.

2. The preparation method according to claim 1, characterized in that, The number-average molecular weight of the polyisobutylene maleic anhydride is 500-5000.

3. The preparation method according to claim 1, characterized in that, The base oil has a kinematic viscosity of 2 mm at 100°C. 2 / s-20mm 2 / s.

4. The preparation method according to claim 1, characterized in that, The aromatic solvent is selected from one or more of benzene, toluene, and xylene.

5. The preparation method according to claim 1, characterized in that, The polyamine is selected from one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and polyethylenepolyamine.

6. The preparation method according to claim 1, characterized in that, The mass ratio of polyisobutylene maleic anhydride, base oil, and aromatic solvent is 1:0.2-1:0.3-2.

7. The preparation method according to claim 1, characterized in that, The molar ratio of the polyethylene polyamine to the polyisobutylene maleic anhydride is 1:1-3.

8. The preparation method according to claim 1, characterized in that, The stirring temperature in step (1) is 50-70℃, and the temperature is raised to 100-120℃. The amidation reaction time is 2-10h.

9. The preparation method according to claim 1, characterized in that, The aminophenylboronic acid mentioned in step (2) is selected from one or more of 2-aminophenylboronic acid, 3-aminophenylboronic acid and 4-aminophenylboronic acid.

10. The preparation method according to claim 9, characterized in that, The molar ratio of aminophenylboronic acid to polyisobutylene maleic anhydride is 1:1-2.

11. The preparation method according to any one of claims 1-10, characterized in that, The borylation reaction in step (2) takes 4-12 hours.

12. A polyisobutylene succinimide dispersant prepared by the method according to any one of claims 1-11.

13. The use of a soot-dispersible polyisobutylene succinimide dispersant prepared by any one of claims 1-11 in the preparation of lubricating oil additives.

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