1. A method of preparing a boron-modified ashless dispersant, comprising:

mixing polyolefin succinic anhydride, a diluent and polyene polyamine at the temperature of 40-80 ℃ to carry out primary reaction;

heating to 80-95 ℃, and adding a boration agent and an accelerant into the material after the primary reaction to perform a secondary reaction; and

heating to 120-160 ℃, and continuously carrying out three reactions on the materials after the secondary reaction to remove the accelerator and water to obtain the boron modified ashless dispersant;

wherein the polyolefin-based succinic anhydride is represented by the following formula I:

wherein R is a polyolefin group with the number average molecular weight of 800-2500, x is the substitution degree of succinic anhydride on R, and x is 0.9-1.3.

2. The method of claim 1, wherein R is a polyisobutenyl group.

3. The method according to claim 1, wherein the molar ratio of the number of carbonyl groups in the polyalkenyl succinic anhydride to the polyene polyamine is (1.5 to 5.5): 1.

4. the process of claim 1, wherein the polyene polyamine has the formula H₂N(CH₂CH₂NH)_nH, wherein n is an integer of 1-4.

5. The method according to claim 4, wherein the polyene polyamine is selected from one or more of ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine.

6. The method according to claim 1, wherein the time for the first reaction is 0.5h to 3h, the time for the second reaction is 1h to 4h, and the time for the third reaction is 2h to 4 h.

7. The method according to claim 1, wherein the diluent is mineral oil, and the mass ratio of the diluent to the polyolefin-based succinic anhydride is (0.5-2): 1.

8. the method of claim 1, wherein the borating agent is selected from one or more of boric acid and metaboric acid and the promoter is selected from one or more of n-butanol, n-pentanol, isobutanol, isoamyl alcohol, and n-hexanol.

9. The method according to claim 1, wherein the mass ratio of the accelerator to the boronating agent is (0.1-4): 1.

10. the method of claim 1, wherein the first, second, and third reactions are performed under an inert atmosphere.

11. A boron-modified ashless dispersant prepared by the method of any one of claims 1 to 10.

12. The boron-modified ashless dispersant of claim 11, wherein the boron content in said boron-modified ashless dispersant is between 0.01 wt% and 2 wt%.

13. Use of the boron-modified ashless dispersant of claim 11 or 12 in a lubricating oil.

Background

The ashless dispersant is a common lubricating oil additive, and has the outstanding performance of inhibiting the gasoline engine oil from generating oil sludge at a lower working temperature of a crankcase, so that the oil circuit in the gasoline engine is prevented from being blocked, and parts are prevented from being corroded and abraded. The representative compound of the ashless dispersant is a succinimide dispersant, however, with the improvement of engine performance and the requirement of environmental protection, the internal combustion engine oil is continuously upgraded and updated, and the ashless dispersant has poor thermal stability when having good low-temperature dispersibility, and can not meet the engine requirement. Research shows that the problem can be obviously improved by adopting the boronized polyisobutylene succinimide ashless dispersant.

At present, the research on the boronized polyisobutylene succinimide ashless dispersant and the preparation method thereof have been reported. For example, CN95107994.8 discloses a post-crosslinked succinimide ashless dispersant. The boron-containing dispersant is prepared by post-crosslinking reaction of a succinimide dispersant and a boronizing agent such as boric acid, boric acid ester and the like, but boron slag is easily generated in the boronizing process, so that post-treatment and use are difficult; US4985156 proposes a method for preparing boron modified ashless dispersant, first mixing ashless dispersant with butanol and toluene, adding boric acid at a certain temperature, heating to 150 ℃ for reflux reaction for 7h to generate a certain amount of water, then filtering to obtain the finished product boron modified ashless dispersant, wherein the boron content of a typical product is 2.25%, the acid value is 44.0mgkOH/g, and the base value is 27.0 mgKOH/g; CN1090877A discloses an improved low-settling method for forming boronated dispersants, but the method must strictly control the particle size of the raw boric acid particles, making the preparation method complicated and cumbersome.

It is noted that the information disclosed in the foregoing background section is only for enhancement of background understanding of the invention and therefore it may contain information that does not constitute prior art that is already known to a person of ordinary skill in the art.

Disclosure of Invention

The invention aims to overcome at least one defect of the prior art and provides a boron modified ashless dispersant, a preparation method and application thereof, so as to solve the problems of poor low-temperature dispersibility, low thermal oxidation stability or difficult post-treatment and use caused by easy generation of boron slag and the like of the conventional ashless dispersant.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a method for preparing a boron modified ashless dispersant, which comprises the following steps: mixing polyolefin succinic anhydride, a diluent and polyene polyamine at the temperature of 40-80 ℃ to carry out primary reaction; heating to 80-95 ℃, and adding a borating agent and an accelerant into the material after the primary reaction to perform a secondary reaction; heating to 120-160 ℃, and continuously carrying out third reaction on the materials after the second reaction to remove the accelerator and water to obtain the boron modified ashless dispersant; wherein the polyolefin-based succinic anhydride is represented by the following formula I:

wherein R is a polyolefin group with the number average molecular weight of 800-2500, x is the substitution degree of succinic anhydride on R, and x is 0.9-1.3.

According to one embodiment of the invention, R is a polyisobutenyl group.

According to one embodiment of the present invention, the molar ratio of the number of carbonyl groups in the polyolefin-based succinic anhydride to the polyene polyamine is (1.5 to 5.5): 1.

according to one embodiment of the invention, the polyene polyamine has the formula H₂N(CH₂CH₂NH)_nH, wherein n is an integer of 1-4.

According to one embodiment of the invention, the polyene polyamine is selected from one or more of ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine.

According to one embodiment of the invention, the time of the first reaction is 0.5h to 3h, the time of the second reaction is 1h to 4h, and the time of the third reaction is 2h to 4 h.

According to one embodiment of the invention, the diluent is selected from one or more of mineral oil, toluene and xylene, and the mass ratio of the diluent to the polyolefin-based succinic anhydride is (0.5-2): 1.

according to one embodiment of the invention, the borating agent is selected from one or more of boric acid, metaboric acid and the promoter is selected from one or more of n-butanol, n-pentanol, isobutanol, isoamyl alcohol and n-hexanol.

According to one embodiment of the present invention, the mass ratio of the accelerator to the boronizing agent is (0.1-4): 1.

according to one embodiment of the present invention, the first reaction, the second reaction and the third reaction are performed under an inert atmosphere.

The invention also provides a boron modified ashless dispersant prepared by the method.

According to one embodiment of the present invention, the boron content in the boron-modified ashless dispersant is 0.01 wt% to 2 wt%.

The invention also provides application of the boron modified ashless dispersant in lubricating oil.

According to the technical scheme, the invention has the beneficial effects that:

compared with the boron modification method for carrying out post-crosslinking on the dispersant, the method has the advantages of simple process and no generation of boron slag in the preparation process. The obtained dispersant product has good low-temperature dispersing performance and outstanding thermal oxidation stability, can be used as a lubricating oil additive, and has good industrial application prospect.

Detailed Description

The following presents various embodiments or examples in order to enable those skilled in the art to practice the invention with reference to the description herein. These are, of course, merely examples and are not intended to limit the invention. The endpoints of the ranges and any values disclosed in the present application are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to yield one or more new ranges of values, which ranges of values should be considered as specifically disclosed herein.

If no special description is provided, the analysis method and the calculation method of each index related to the invention are as follows:

1. saponification value analysis method: SY 2604-77.

2. The nitrogen content analysis method comprises the following steps: SH/T0656-2017.

3. The boron content analysis method comprises the following steps: GB/T17476-1998

4. Molecular weight analysis methods (Mn, Mw, and Mw/Mn) SH/T0108-92.

5. Initial decomposition temperature of lubricating oil additive: the measurement was carried out with a differential scanning calorimeter (DSC method).

6.

Wherein Mn is the number average molecular weight of the polyolefin base, and the saponification value is expressed in mg KOH/g, namely the mg of KOH consumed by titration of 1g of the product; the substitution degree x is derived from the number of acid anhydrides in the molecules of the polyolefin succinic anhydride and is defined according to the saponification value.

The invention provides a method for preparing a boron modified ashless dispersant, which comprises the following steps: mixing polyolefin succinic anhydride, a diluent and polyene polyamine at the temperature of 40-80 ℃ to carry out primary reaction; heating to 80-95 ℃, and adding a borating agent and an accelerant into the material after the primary reaction to perform a secondary reaction; heating to 120-160 ℃, and continuously carrying out third reaction on the materials after the second reaction to remove the accelerator and water to obtain the boron modified ashless dispersant; wherein the polyolefin-based succinic anhydride is represented by the following formula I:

wherein R is a polyolefin group with the number average molecular weight of 800-2500, and in some embodiments, R is selected from a polyisobutenyl group, a polypropylene group or an ethylene-propylene copolymer group, and is preferably a polyisobutenyl group; x is the substitution degree of succinic anhydride on R, and x is 0.9-1.3.

According to the present invention, the currently available ashless dispersants generally cannot achieve both low temperature dispersibility and thermal stability, and therefore need to be boron-modified. However, the conventional boron modification method is obtained by post-crosslinking reaction of the existing ashless dispersant product and a boronizing agent, and boron slag is easily generated in the boronizing process, so that the post-treatment and the use are difficult. The inventor of the invention finds that boron modification can be directly carried out in the process of preparing the ashless dispersant by strictly controlling the reaction charging sequence and the reaction temperature, so that the boronized modified ashless dispersant can be obtained by a one-step method, and the ashless dispersant obtained by the method has good low-temperature dispersibility and higher thermal stability and does not generate boron slag.

Specifically, firstly, the polyolefin succinic anhydride, the diluent and the polyene polyamine are mixed at 40-80 ℃, and the reaction is carried out for one time at the temperature, wherein the reaction time is 0.5-3 h, such as 0.5h, 1h, 2h, 2.5h, 3h and the like. For example, polyisobutenyl succinic anhydride, which is commercially available or can be prepared by alkylation of Polyisobutylene (PIB) with maleic anhydride, is shown in formula II below, wherein R is a polyisobutylene substituent group:

the obtained polyisobutylene succinic anhydride and the polyene polyamine are further reacted, wherein due to excessive viscosity of reactants, a diluent is required for dilution, preferably, the diluent can be mineral oil, toluene, xylene or the like, and the mineral oil is preferably 150 SN. The mass ratio of the diluent to the polyolefin succinic anhydride is (0.5-2): 1, e.g., 0.5:1, 1:1, 2:1, etc. The polyisobutylene succinic anhydride and the polyene polyamine with different molar ratios can prepare the mono-polyisobutylene succinimide, the di-polyisobutylene succinimide or the mixture of the mono-polyisobutylene succinimide and the di-polyisobutylene succinimide. In the invention, the molar ratio of the number of carbonyl groups in the polyolefin succinic anhydride to the polyene polyamine is (1.5-5.5): 1, preferably (2-5): 1, e.g., 2:1, 3:1, 4.5:1, etc. The molar ratio affects the structure of the generated ashless dispersant, for example, when the molar ratio is 2:1, most of the synthesized ashless dispersant is a singly-hung polyisobutylene succinimide structure, when the molar ratio is 4:1, most of the synthesized ashless dispersant is a doubly-hung polyisobutylene succinimide structure, and the molar ratio is between 2:1 and 4:1, a mixture of singly-hung polyisobutylene succinimide and doubly-hung polyisobutylene succinimide is generally obtained, and when the molar ratio is more than 4:1, a multiply-hung polyisobutylene succinimide structure is generated, but the invention needs to carry out a boronization reaction, and the multiply-hung polyisobutylene succinimide structure is not beneficial to the boronization reaction.

The polyene polyamine has the formula H₂N(CH₂CH₂NH)_nH, wherein n is an integer of 1-4. Specifically, the polyene polyamine may be selected from one or more of ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine. The polyisobutylene succinic anhydride and the polyene polyamine can be added into the reactor simultaneously or sequentially in batches, the adding temperature is preferably not higher than 80 ℃, for example, 50 ℃, 65 ℃, 70 ℃, 75 ℃ and the like, and the reaction time is 0.5h to 3h, so as to ensure that the ring opening reaction of the polyisobutylene succinic anhydride and the polyene polyamine is completed. After the addition of the polyene polyamine, the polyene polyamine and the polyisobutylene succinic anhydride can generate a ring-opening reaction, the reaction is rapid, a large amount of heat can be emitted in a short time, the temperature of a reaction system is increased sharply, secondary amine of the polyene polyamine can participate in the reaction after the temperature of the reaction system is increased sharply, a multi-hanging structure is generated, the contact reaction temperature of the polyene polyamine and the polyisobutylene succinic anhydride is strictly controlled due to the control of the reaction temperature, and the polyene polyamine is added in a dropwise manner in an experiment to ensure the subsequent boronization reactionThe process is carried out.

Then, the reaction system is heated to 80 ℃ to 95 ℃, for example, 85 ℃, 90 ℃, 92 ℃, 95 ℃ and the like, and the boration agent and the accelerant are added into the materials after the primary reaction for secondary reaction for 1h to 4h, for example, 1.5h, 2h, 3.5h, 4h and the like. Wherein the borating agent can be boric acid, metaboric acid or a mixture of the boric acid and the metaboric acid, and the promoter is selected from one or more of n-butanol, n-pentanol, isobutanol, isoamyl alcohol and n-hexanol. In the secondary reaction process, partial water generated in the primary reaction and the added alcohol accelerator can be utilized to decompose the boronizing agent into a single molecular state, so that the boron in a compound state is directly connected with nitrogen in the primary reaction product, the thermal stability and the storage stability are improved, and the formation of boron slag is reduced by the method of directly reacting but not post-crosslinking.

The mass ratio of the accelerator to the boronizing agent is (0.1-4): 1, e.g., 0.1:1, 0.5:1, 1:1, 2:1, 3:1, 3.5:1, 4:1, etc. The ratio of the promoter to the boronizing agent is too low to facilitate the boronizing reaction, thereby causing boron slag residue. An excessively large proportion promotes the boronation reaction, but increases the evaporation of the solvent after the reaction. The dosage of the boronizing agent is to ensure that the boron content of the final product reaches 0.01 wt% -2 wt%, and the final performance of the product under the proportion is better. The excessive addition of the boronizing agent can cause the residue of boron slag, so the addition of the boronizing agent is very small, and the addition of the boronizing agent is generally calculated according to the quality index of the ashless dispersant theoretically generated and the theoretical boron content in the reaction process.

And further, after the second reaction is finished, continuously heating the reaction system to 120-160 ℃ for third reaction, and mainly removing the alcohol accelerator and the water to obtain the final product of the boronized modified ashless dispersant. The time for the three reactions is generally 2h to 4h, such as 2h, 3.5h, 3h, 4h and the like. The first reaction, the second reaction, and the third reaction are preferably carried out under an inert atmosphere.

In conclusion, the invention controls the feeding sequence and reaction temperature of the reaction raw materials, and utilizes the characteristics of the reaction, so that the boron in a compound state can be effectively combined into the product, the thermal stability and storage stability of the product are improved, meanwhile, the method of direct one-step reaction rather than post-crosslinking is also favorable for reducing the formation of boron slag, and the obtained boron modified ashless dispersant has excellent performance and has good industrial application prospect when being applied to lubricating oil as an additive.

The invention will be further illustrated by the following examples, but is not to be construed as being limited thereto. Unless otherwise specified, the reagents used in the present invention are commercially available.

Example 1

Adding 100g of polyisobutylene succinic anhydride (the number-average molecular weight Mn of polyisobutylene is 1000, the saponification value is 93 mg KOH/g, and x is 0.9) and 50g of 150SN base oil (Shanghai Gaoqiao petrochemical company, Inc.), heating to 40 ℃, uniformly stirring, adding 7.84g of triethylene tetramine (CP, national reagent, Inc.) under the protection of nitrogen, controlling the temperature to be 40-80 ℃, reacting for 0.5h, then heating to 90 ℃, adding 0.94g of boric acid (AR, national reagent, Inc.) and 0.09g of n-butyl alcohol (AR, national reagent, Inc.) and continuing to react for 3h at the temperature, then heating to 160 ℃ and reacting for 2h to obtain the final boronized ashless dispersant, wherein the molar ratio of the number of carbonyl to tetraethylenepentamine is 4:1, the weight ratio of the diluent to the polyisobutylene succinic anhydride is 0.5:1, the weight ratio of the accelerator to the boric acid is 0.1:1, no unreacted boric acid residue is found after the product is filtered.

Example 2

100g of polyisobutylene succinic anhydride (number average molecular weight Mn of polyisobutylene is 1300, saponification number 86 mg KOH/g, x is 1.07) and 100g of 150SN base oil are added into a three-neck flask, heated to 40 ℃ and stirred uniformly, under the protection of nitrogen, 14.51g of tetraethylenepentamine (CP, national reagent Co., Ltd.) is added, the temperature is controlled at 40-80 ℃, the reaction is carried out for 0.5h, then heated to 90 ℃ and added with 39.50g of boric acid and 158g of isoamyl alcohol (AR, national reagents Co., Ltd.), continuously reacting for 3 hours at the temperature, then heating to 160 ℃ for reacting for 2 hours to obtain the final boronized ashless dispersant, the molar ratio of the number of carbonyl to the tetraethylenepentamine of the product is 2:1, the weight ratio of the diluent to the polyisobutylene succinic anhydride is 1:1, the weight ratio of the accelerator to the boric acid is 4:1, and no unreacted boric acid residue is found after the product is filtered.

Example 3

100g of polyisobutylene succinic anhydride (number average molecular weight Mn of polyisobutylene 2300, saponification number 60 mg KOH/g, and x of 1.3) and 200g of 150SN base oil were put into a three-neck flask, heated to 40 ℃ and stirred uniformly, under the protection of nitrogen, 4.05g of tetraethylenepentamine is added, the temperature is controlled to be 40-80 ℃, the reaction is carried out for 0.5h, then the temperature is raised to 90 ℃, 18.89g of metaboric acid (AR, national reagent Co., Ltd.) and 37.79g of n-hexanol (AR, national reagent Co., Ltd.) are added, continuously reacting for 3 hours at the temperature, then heating to 160 ℃ for reacting for 2 hours to obtain the final boronized ashless dispersant, the molar ratio of the number of carbonyl to the tetraethylenepentamine of the product is 5:1, the weight ratio of the diluent to the polyisobutylene succinic anhydride is 2:1, the weight ratio of the accelerator to the boric acid is 2:1, and no unreacted boric acid residue is found after the product is filtered.

Comparative example 1

Adding 100g of polyisobutylene succinic anhydride (the number-average molecular weight Mn of polyisobutylene is 1000, the saponification value is 93 mg KOH/g, and x is 0.9) and 50g of 150SN base oil into a three-neck flask, heating to 40 ℃, uniformly stirring, adding 7.84g of triethylene tetramine under the protection of nitrogen, controlling the temperature to be 40-80 ℃, reacting for 0.5h, then heating to 160 ℃, and reacting for 2 hours to obtain the final ashless dispersant, wherein the molar ratio of the number of carbonyl to tetraethylenepentamine of the product is 4:1, and the weight ratio of the diluent to the polyisobutylene succinic anhydride is 0.5: 1.

Comparative example 2

Adding 100 polyisobutylene succinimide (the number average molecular weight Mn of polyisobutylene is 1300) into a three-neck bottle, introducing nitrogen, heating to 80-85 ℃, adding 400 g of n-butyl alcohol and 6g of boric acid with the particle size less than 100 micrometers, reacting for 4 hours, distilling under reduced pressure for 2.5 hours, and removing micromolecular substances to obtain the final product. The product was filtered and found to have unreacted boric acid sludge.

Comparative example 3

Adding 100 polyisobutylene succinimide (the number average molecular weight Mn of polyisobutylene is 2300) into a three-neck flask, introducing nitrogen, heating to 80-85 ℃, adding 400 g of n-butyl alcohol and 6g of boric acid with the particle size less than 100 micrometers, reacting for 4 hours, distilling under reduced pressure for 2.5 hours, and removing micromolecular substances to obtain the final product. The product was filtered and found to have unreacted boric acid sludge.

Test example 1

The materials obtained in examples 1 to 3 and comparative examples 1 to 3 were subjected to performance tests, and the test results are shown in Table 1. As can be seen from the following table 1, compared with the materials of comparative examples 1-3, the boronized ashless dispersant prepared by the method has outstanding thermal oxidation stability, basically no precipitate is separated out from the product after the reaction is finished, and the boronized ashless dispersant has good application prospect.

TABLE 1

	Initial decomposition temperature/. degree.C	Nitrogen content, w%	Boron content, w%	Filter residue/g
					Example 1	285	1.43	0.1	0
Example 2	292	2.22	2.0	0
					Example 3	315	0.47	1.0	0
Comparative example 1	270	1.44	0	0
					Comparative example 2	289	2.24	1.9	1.5
Comparative example 3	314	1.19	0.89	0.7

In conclusion, the invention provides a method for directly preparing a boronized modified ashless dispersant by a one-step method, compared with a post-crosslinking boron modification method, the method has the advantages of simple process and no generation of boron slag in the preparation process. The obtained dispersant product has good low-temperature dispersing performance and outstanding thermal oxidation stability, can be used as a lubricating oil additive, and has good industrial application prospect.

It should be noted by those skilled in the art that the described embodiments of the present invention are merely exemplary and that various other substitutions, alterations, and modifications may be made within the scope of the present invention. Accordingly, the present invention is not limited to the above-described embodiments, but is only limited by the claims.