Preparation method of low-sulfur diesel anti-wear agent

Abstract

The application provides a preparation method of a low-sulfur diesel oil anti-wear agent and belongs to the technical field of carbon-containing fuel processing, and comprises the following steps: sodium oleate, tetrabutylammonium bromide and dimethylbenzene are added into a three-necked flask, stirred and uniformly mixed, heated, 3-chloro-1,2-propanediol is added dropwise, heating is continued until reflux, centrifugation, rotary evaporation are carried out, and glycerol monooleate is obtained; the NCC is dispersed in dimethylbenzene, lauric acid and p-toluenesulfonic acid are added, heating is carried out under the protection of an inert atmosphere, reflux reaction is carried out, cooling is carried out, centrifugation is carried out, washing is carried out, drying is carried out, and modified NCC is obtained; the glycerol monooleate is heated and melted, silane-modified silicon dioxide is added, stirring, ultrasonic treatment, cooling are carried out, modified nanocomposites are obtained, the modified NCC and a stabilizer are further added, stirring and ultrasonic treatment are carried out, and the low-sulfur diesel oil anti-wear agent is obtained. The diesel oil anti-wear agent can improve the anti-wear performance of diesel oil under the condition of a low addition amount, and can improve the low-temperature fluidity and demulsification performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon-containing fuel processing, in particular to a preparation method of low-sulfur diesel anti-wear agent. BACKGROUND

[0002] With the improvement of low-sulfur emission environmental protection requirements, the quality requirements for commonly used liquid fuels are also becoming more and more strict, among which the sulfur content of diesel is required to be less than 150 μg / g. However, sulfur compounds are natural lubricants, and after the sulfur compounds are removed by hydrofining, the lubricity will also be lost, resulting in wear of diesel engine during operation, and even oil leakage accidents or machine failures may occur in severe cases. Therefore, the quality of diesel is also required to have lubricating performance, i.e. anti-wear performance, which is generally measured by wear scar diameter, and the wear scar diameter is required to be less than 460 μm. When the sulfur content of diesel after hydrofining is less than 150 μg / g, the wear scar diameter is between 500-800 μm, and the lower the sulfur content, the larger the wear scar diameter. Therefore, in order to meet the requirements of the lubricating performance of diesel, diesel anti-wear agent needs to be added in the subsequent processing of diesel.

[0003] At present, the addition amount of diesel anti-wear agent generally needs to be 50-300 ppm, and the addition amount of diesel anti-wear agent should not be too large to avoid affecting the combustion performance of diesel itself and increasing the production cost, so it is necessary to achieve good anti-wear effect with as low an amount of diesel anti-wear agent as possible. Glycerol monooleate is a good diesel anti-wear agent component, especially glycerol monooleate, because only one oleic acid chain exists in the molecule, and the remaining two hydroxyl groups remain free, so it has stronger polarity and is more easily adsorbed on the metal surface, and can form a more dense lubricating film, thereby effectively isolating the direct contact of the friction pair, and has strong anti-wear effect. The hydroxyl groups of multi-oleic glycerol esters, such as glycerol dioleate and glycerol trioleate, are replaced by more oleic acid chains, which reduces the molecular polarity and makes it more inclined to dissolve in the oil phase rather than adsorb on the metal surface, resulting in weak ability to form a lubricating film and weak anti-wear effect, so the input amount needs to be increased to improve the anti-wear effect. However, in the process of synthesizing glycerol monooleate by esterification, multi-oleic glycerol esters are easily produced, and it is difficult to obtain glycerol monooleate with high yield, resulting in a large amount of multi-oleic glycerol esters in the glycerol monooleate obtained by general synthesis method, low content of glycerol monooleate, and general anti-wear effect, which requires an increase in the addition amount.

[0004] However, glycerol monooleate may affect the low-temperature flow performance of diesel during use, and is more prone to emulsification, which limits its application in diesel anti-wear agent, so it is also necessary to improve the low-temperature flow performance and demulsification performance of glycerol monooleate in diesel. SUMMARY

[0005] Therefore, the application provides a preparation method of a low-sulfur diesel anti-wear agent, which can improve the anti-wear performance of diesel, and improve the low-temperature fluidity and demulsification performance under a low addition amount.

[0006] To achieve the above-mentioned object, the application provides a preparation method of a low-sulfur diesel anti-wear agent, which comprises the following steps:

[0007] S1. Sodium oleate, tetrabutylammonium bromide and dimethylbenzene are added into a three-necked flask, stirred and uniformly mixed, heated, 3-chloro-1,2-propanediol is added dropwise, and heating is continued until reflux, centrifugation, rotary evaporation, and a single glycerol monooleate is obtained;

[0008] S2. The NCC is dispersed in dimethylbenzene, lauric acid and p-toluenesulfonic acid are added, heated under the protection of an inert atmosphere, and refluxed, cooled, centrifuged, washed and dried to obtain modified NCC;

[0009] S3. The single glycerol monooleate is heated and melted, silane-modified silicon dioxide is added, stirred, ultrasonically treated, and cooled to obtain modified nanocomposites, and then the modified NCC and the stabilizer are added, and stirring and ultrasonic mixing are performed to obtain the low-sulfur diesel anti-wear agent.

[0010] In the application, sodium oleate and 3-chloro-1,2-propanediol are used as raw materials, and a substitution reaction is carried out under the catalysis of tetrabutylammonium bromide to efficiently obtain a single glycerol monooleate (GMO). The whole process does not need to carry out an esterification reaction, so that the yield and purity of GMO can be improved, and the GMO can be synthesized to the greatest extent to have the best anti-wear effect. The GMO can be easily adsorbed on a metal surface to form a dense lubricating film, so that the lubricating effect can be significantly improved, and a good anti-wear effect can be achieved by adding a small amount. The solvent can be easily recovered by rotary evaporation, and the method is economical and environmentally friendly.

[0011] The NCC (nanocrystalline cellulose) is esterified and modified by lauric acid and p-toluenesulfonic acid to obtain modified NCC. The modified NCC can form a network structure to improve the bearing effect, and more ester bonds can be generated after the esterification of the NCC to improve the oil solubility and lubricating effect, improve the anti-wear effect, overcome the problems of easy agglomeration, poor dispersibility and stability of the NCC by using the hydrophobic long chain of grafted lauric acid, enhance the dispersion stability of the NCC in fuel, and further improve the anti-wear effect by adsorbing the lauric acid on the metal surface to form an anti-wear film. In addition, the modified NCC is degradable, and meets the requirements of green fuel.

[0012] The modified nanocomposite is obtained by heating and melting the monoglyceride oleic acid and then blending with the silane modified silicon dioxide, so that the silane modified silicon dioxide nanoparticles in the composite preferentially absorb on the oil-water interface, occupy the emulsification sites, reduce the emulsification tendency of the monoglyceride oleic acid, and meanwhile, the hydrophobic nanoparticles of the silane modified silicon dioxide can also serve as a physical barrier to interfere with the ordered arrangement of the monoglyceride oleic acid molecular chain, thereby reducing the crystallinity and improving the low-temperature flow performance.

[0013] Preferably, the stabilizer is PIBSI / calcium borate hybrid particles obtained by hybridizing PIBSI with calcium borate.

[0014] The PIBSI / calcium borate hybrid particles obtained by hybridizing PIBSI with calcium borate can not only play the role of dispersion and stabilization as a stabilizer, but also can play the anti-wear effect of calcium borate to improve the anti-wear effect, and by hybridizing PIBSI with calcium borate, the defects of high wear resistance and easy hydrolysis of calcium borate are overcome, so that the hybrid particles simultaneously have the functions of anti-wear, dispersion and stabilization.

[0015] Preferably, the PIBSI / calcium borate hybrid particles are prepared by the following method: dissolving PIBSI and Span-80 in n-heptane to obtain an oil phase, adding part of the oil phase to a calcium nitrate solution, shearing to obtain a microemulsion wrapped with Ca 2+ , taking the remaining oil phase to add a borax solution, shearing to obtain a microemulsion wrapped with B4O7 2- , mixing with the microemulsion wrapped with Ca 2+ , heating, stirring and reacting, adding acetone for demulsification, centrifuging, washing, vacuum drying to obtain the PIBSI / calcium borate hybrid particles.

[0016] Calcium borate has poor hydrolysis stability, is easy to absorb moisture in the air or trace water in fuel oil to hydrolyze, generate boric acid and calcium hydroxide, among which boric acid is easy to crystallize and precipitate, and calcium hydroxide is easy to form soap substances, resulting in turbidity and deposition of diesel oil, and calcium borate is easy to agglomerate and settle, affecting the play of anti-wear effect.

[0017] The present application first prepares a microemulsion wrapped with B4O7 2- and a microemulsion wrapped with Ca 2+The microemulsion and the two are mixed and stirred to react, so that the microemulsion droplets collide with each other, ion exchange occurs in the internal water nucleus, calcium borate nanoparticles are generated, and are quickly wrapped in situ by PIBSI molecules. The imide group polar head of the PIBSI molecules is easily combined with the calcium ions on the surface of the calcium borate particles through coordination bonds, so that a dense hydrophobic organic molecular layer is formed, like a "raincoat" to block the contact of water molecules with the inner core calcium borate. At the same time, the large polyisobutylene chain of PIBSI can fully stretch in diesel, producing a large steric hindrance effect, which can ensure that the PIBSI / calcium borate hybrid particles can be stably dispersed and not agglomerated, thereby fundamentally solving the problems of easy hydrolysis and agglomeration of calcium borate. At the same time, the anti-wear effect is also improved. Under the high temperature and high pressure of the friction pair, the PIBSI / calcium borate hybrid particles are easily released to release active boron elements, react with the metal surface to generate a very hard iron boride wear-resistant layer, repair and anti-wear, and the polar end of PIBSI can be firmly adsorbed on the metal surface, and the hydrophobic long chain forms a lubricating film, so that the "chemical reaction film" and "physical adsorption film" are achieved. Double protection, improve the anti-wear effect.

[0018] PIBSI / calcium borate hybrid particles contain PIBSI, which is a good stabilizer and can make the anti-wear agent maintain good dispersion and stability. No other stabilizer needs to be added separately, and the performance of the anti-wear agent is also avoided. Influenced by other complex substances; at the same time, the polar head of the PIBSI molecule and the nano hybrid particles themselves will preferentially adsorb on the first precipitated wax crystal nucleus, interfere with the directional growth of the wax crystal, thereby delaying the gelation process of diesel, reducing the cold filter plugging point (CFPP), and further improving the low temperature flow performance.

[0019] However, PIBSI itself is an oil-in-water (O / W) emulsifier that can easily affect demulsification performance. The PIBSI hybrid calcium borate nanoparticles formed by hybridizing PIBSI to calcium borate nanoparticles can compete with other existing emulsion impurities for oil-water interface positions, thereby destroying the integrity of the interface film, promoting rapid oil-water separation, and improving demulsification performance.

[0020] Preferably, in the preparation process of the PIBSI / calcium borate hybrid particles, the shearing condition is 8000-10000 rpm shearing for 15 min, and the Ca 2+The microemulsion is mixed, heated to 40℃, stirred at 500 rpm for 24 hours, demulsified by adding an equal volume of acetone, centrifuged at 6000-8000 rpm for 10 min, the precipitate is collected, washed 3 times with a 1:1 ethanol-acetone mixture, and dried at 60℃ under vacuum for 12 hours to obtain PIBSI / calcium borate hybrid particles; the calcium nitrate solution is prepared by dissolving 10-15 parts of calcium nitrate in 100 parts of deionized water; the borax solution is prepared by dissolving 13-19 parts of borax in 100 parts of deionized water.

[0021] By adding an equal volume of acetone after the end of the stirring reaction to precipitate the hybrid particles, centrifugation collection is facilitated, and washing with an ethanol-acetone mixture can better remove residual surfactants and salt impurities.

[0022] Preferably, the NCC is prepared by mixing wood fibers with sulfuric acid, heating and stirring, adding deionized water for dilution, centrifuging, collecting the precipitate for dialysis, and freeze-drying to obtain NCC.

[0023] Preferably, the NCC is prepared by mixing wood fibers with 60wt% sulfuric acid at a mass ratio of 1:5, heating to 45℃ for magnetic stirring for 3 hours, adding deionized water for dilution, centrifuging at 8000 rpm for 25 min, collecting the precipitate, dialysis with a molecular weight cutoff of 12-15 kDa, and freeze-drying to obtain NCC.

[0024] The present application uses wood fibers to hydrolyze the amorphous region in the wood fibers by acid, retains the high crystallinity of nanocellulose structure, and then links lauric acid to the hydroxyl groups (-OH) on the surface of NCC through esterification reaction, thereby imparting the modified NCC with fuel compatibility and anti-wear performance.

[0025] Preferably, the silane-modified silica is prepared by dispersing SiO2 nanoparticles with a particle size of 50 nm in ethanol, ultrasonic treatment for 25 min, adding octadecyltrimethoxysilane, centrifuging after stirring at 65℃ for 4h, and washing and drying to obtain silane-modified silica.

[0026] Preferably, in step S1, heating to 88℃, slowly adding 3-chloro-1,2-propanediol after the sodium oleate is completely dissolved, continuing to heat until reflux, centrifuging at 3000 rpm for 12 min, collecting the oil phase, and rotary evaporation at 55-65℃ to obtain glyceryl monooleate.

[0027] The above preparation method uses substitution reaction, does not require esterification reaction, and does not require high temperature, so that glyceryl monooleate can be synthesized at much lower than 100℃, effectively reducing the generation of byproducts, with higher yield, and the solvent can be recovered.

[0028] Preferably, in the step S2, the NCC is dispersed in xylene, ultrasonic treatment is performed for 25 min, lauric acid and p-toluene sulfonic acid are added, heating is performed to 112 DEG C under nitrogen protection, reflux reaction is performed for 6 h, cooling is performed, centrifugation is performed at a rotating speed of 5000 rpm for 8 min, a precipitate is obtained, washing is performed with xylene for 3 times, washing is performed with acetone for 3 times, and then drying is performed at 55 DEG C for 12 h to obtain the modified NCC.

[0029] Preferably, in the step S3, the temperature for heating and melting of the glycerol monooleate is 65 DEG C, after melting, the silane modified silica is added, stirring is performed for 25 min at a rotating speed of 800 rpm, and then ultrasonic treatment is performed for 40 min, cooling is performed to room temperature to obtain the modified nanocomposite, the modified NCC and the stabilizer are added, stirring is performed for 10 min, and ultrasonic mixing is performed for 20 min to obtain the low-sulfur diesel anti-wear agent.

[0030] Preferably, the low-sulfur diesel anti-wear agent comprises the following mass fractions of substances: 20-30 parts of glycerol monooleate, 0.5-2 parts of silane modified silica, 1-3 parts of modified NCC and 0.5-1.5 parts of stabilizer.

[0031] Preferably, the glycerol monooleate comprises the following mass fractions of raw materials: 30-60 parts of sodium oleate, 2-5 parts of tetrabutylammonium bromide, 300-400 parts of xylene, 22-45 parts of 3-chloro-1,2-propanediol; the silane modified silica comprises the following mass fractions of raw materials: 1-2 parts of SiO2, 0.5-1 part of octadecyltrimethoxysilane; the modified NCC comprises the following mass fractions of raw materials: 30-50 parts of wood fiber, 150-250 parts of sulfuric acid with a concentration of 60 wt%, 200-300 parts of xylene, 15-23 parts of lauric acid and 1.5-2.5 parts of p-toluene sulfonic acid; and the stabilizer is PIBSI / calcium borate hybrid particles, which comprises the following mass fractions of raw materials: 10-15 parts of calcium nitrate, 13-19 parts of borax, 13-20 parts of PIBSI, 1.2-2 parts of Span-80 and 400-500 parts of n-heptane.

[0032] By using the above-mentioned component ratio, the overall dosage of the anti-wear agent is more optimal, and the anti-wear effect and low-temperature flow performance are better.

[0033] The above technical scheme of the present application at least has the following beneficial effects:

[0034] 1. This invention uses sodium oleate and 3-chloro-1,2-propanediol as raw materials to carry out a substitution reaction under the catalysis of tetrabutylammonium bromide, so as to efficiently obtain GMO. The whole process does not require esterification reaction, thus avoiding the generation of diglycerides and triglycerides during the reaction, which would affect the yield and purity of GMO. GMO is easily adsorbed on the metal surface to form a dense lubricating film, thereby significantly improving the lubrication effect. Moreover, only a small amount is needed to achieve good anti-wear effect.

[0035] 2. This invention modifies NCC by esterification with lauric acid and p-toluenesulfonic acid to obtain modified NCC. This modified NCC can improve the load-bearing capacity by forming a network structure, and it can also improve the oil solubility and lubrication by generating more ester bonds after NCC esterification, thereby improving the anti-wear effect. Furthermore, the hydrophobic long chains of grafted lauric acid are used to overcome the problems of NCC's easy agglomeration, poor dispersibility and instability, thereby enhancing the dispersion stability of NCC in fuel. Finally, the anti-wear effect is further improved by the adsorption of lauric acid on the metal surface to form an anti-wear film.

[0036] 3. This invention obtains a modified nanocomposite by heating and melting glyceryl monooleate and then blending it with silane-modified silica. The silane-modified silica nanoparticles in the composite preferentially adsorb at the oil-water interface, occupying emulsification sites and reducing the emulsification tendency of glyceryl monooleate. At the same time, the hydrophobic nanoparticles of silane-modified silica can also interfere with the orderly arrangement of glyceryl monooleate molecular chains, reduce crystallinity, and thus improve low-temperature flow properties. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are some embodiments of the present invention, and all other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0038] Preparation Example 1

[0039] A calcium nitrate solution was prepared by dissolving 10 parts of calcium nitrate in 100 parts of deionized water, and a borax solution was prepared by dissolving 13 parts of borax in 100 parts of deionized water. A borax solution was prepared by dissolving 13 parts of PIBSI and 1.2 parts of Span-80 in 400 parts of n-heptane and stirring thoroughly to form a transparent oil phase. Half the volume of this oil phase was slowly added to the calcium nitrate solution, and the mixture was sheared at 8000 rpm for 15 minutes using a shear mill to obtain a calcium nitrate-coated solution. 2+ The microemulsion was prepared by slowly adding the other half volume of the oil phase to a borax solution and shearing it at 8000 rpm for 15 minutes using a shear mill to obtain a microemulsion coated with B4O7. 2- Microemulsions, with Ca encapsulated2+ The microemulsions were mixed, heated to 40°C, and stirred at 500 rpm for 24 hours. An equal volume of acetone was added to break the emulsion. The mixture was centrifuged at 6000 rpm for 10 minutes, and the precipitate was collected. The precipitate was washed three times with a 1:1 ethanol-acetone mixture and dried under vacuum at 60°C for 12 hours to obtain PIBSI / calcium borate hybrid particles.

[0040] Preparation Example 2

[0041] A calcium nitrate solution was prepared by dissolving 13 parts of calcium nitrate in 100 parts of deionized water, and a borax solution was prepared by dissolving 16 parts of borax in 100 parts of deionized water. A borax solution was prepared by dissolving 18 parts of PIBSI and 1.8 parts of Span-80 in 450 parts of n-heptane and stirring thoroughly to form a transparent oil phase. Half the volume of this oil phase was slowly added to the calcium nitrate solution, and the mixture was sheared at 9000 rpm for 15 minutes using a shear mill to obtain a calcium nitrate-coated solution. 2+ The microemulsion was prepared by slowly adding the other half volume of the oil phase to a borax solution and shearing it at 9000 rpm for 15 minutes using a shear mill to obtain a microemulsion coated with B4O7. 2- Microemulsions, with Ca encapsulated 2+ The microemulsions were mixed, heated to 40°C, and stirred at 500 rpm for 24 hours. An equal volume of acetone was added to break the emulsion. The mixture was centrifuged at 7000 rpm for 10 minutes, and the precipitate was collected. The precipitate was washed three times with a 1:1 ethanol-acetone mixture and dried under vacuum at 60°C for 12 hours to obtain PIBSI / calcium borate hybrid particles.

[0042] Preparation Example 3

[0043] A calcium nitrate solution was prepared by dissolving 15 parts of calcium nitrate in 100 parts of deionized water, and a borax solution was prepared by dissolving 19 parts of borax in 100 parts of deionized water. A borax solution was prepared by dissolving 20 parts of PIBSI and 1 part of Span-80 in 500 parts of n-heptane and stirring thoroughly to form a transparent oil phase. Half the volume of this oil phase was slowly added to the calcium nitrate solution, and the mixture was sheared at 10,000 rpm for 15 minutes using a shear mill to obtain a calcium nitrate-coated solution. 2+ The microemulsion was prepared by slowly adding the other half volume of the oil phase to a borax solution and shearing it at 10,000 rpm for 15 minutes using a shear mill to obtain a microemulsion coated with B4O7. 2- Microemulsions, with Ca encapsulated 2+ The microemulsions were mixed, heated to 40°C, and stirred at 500 rpm for 24 hours. An equal volume of acetone was added to break the emulsion. The mixture was centrifuged at 8000 rpm for 10 minutes, and the precipitate was collected. The precipitate was washed three times with a 1:1 ethanol-acetone mixture and dried under vacuum at 60°C for 12 hours to obtain PIBSI / calcium borate hybrid particles.

[0044] Example 1

[0045] Into a three-necked flask, 30 parts of sodium oleate, 2 parts of catalyst tetrabutylammonium bromide, 300 ml of solvent dimethylbenzene were added, stirred, heated to 88°C, and 22 parts of 3-chloro-1,2-propanediol was slowly added dropwise. The temperature was continuously increased until reflux. The oil phase was collected by centrifugation at 3000 rpm for 12 min, and the oil phase was collected by rotary evaporation at 55°C to obtain glycerol monooleate (GMO).

[0046] Into a three-necked flask, 30 parts of sodium oleate, 2 parts of catalyst tetrabutylammonium bromide, 300 ml of solvent dimethylbenzene were added, stirred, heated to 88°C, and 22 parts of 3-chloro-1,2-propanediol was slowly added dropwise. The temperature was continuously increased until reflux. The oil phase was collected by centrifugation at 3000 rpm for 12 min, and the oil phase was collected by rotary evaporation at 55°C to obtain glycerol monooleate (GMO).

[0047] Into a three-necked flask, 30 parts of sodium oleate, 2 parts of catalyst tetrabutylammonium bromide, 300 ml of solvent dimethylbenzene were added, stirred, heated to 88°C, and 22 parts of 3-chloro-1,2-propanediol was slowly added dropwise. The temperature was continuously increased until reflux. The oil phase was collected by centrifugation at 3000 rpm for 12 min, and the oil phase was collected by rotary evaporation at 55°C to obtain glycerol monooleate (GMO).

[0048] Example 2

[0049] Into a three-necked flask, 30 parts of sodium oleate, 2 parts of catalyst tetrabutylammonium bromide, 300 ml of solvent dimethylbenzene were added, stirred, heated to 88°C, and 22 parts of 3-chloro-1,2-propanediol was slowly added dropwise. The temperature was continuously increased until reflux. The oil phase was collected by centrifugation at 3000 rpm for 12 min, and the oil phase was collected by rotary evaporation at 55°C to obtain glycerol monooleate (GMO).

[0050] Mix 40 parts of lignocellulose with 200 parts of 60 wt% sulfuric acid, heat to 45°C and stir magnetically for 3 hours, dilute with 2000 parts of deionized water, centrifuge at 8000 rpm for 25 min, collect the precipitate, dialyze against a 12-15 kDa molecular weight cutoff, freeze-dry to obtain white powder NCC, disperse in 250 parts of xylene, sonicate for 25 min at a power of ≤200 W to prevent breakage of the NCC crystals, add 20 parts of lauric acid and 2 parts of p-toluenesulfonic acid (PTSA), heat to 112°C under a nitrogen atmosphere, reflux for 6 h, cool, centrifuge at 5000 rpm for 8 min, obtain the precipitate, wash with xylene 3 times, wash with acetone 3 times to remove unreacted lauric acid and p-toluenesulfonic acid, then dry at 55°C for 12 h to obtain modified NCC.

[0051] Disperse 1.5 parts of SiO2 nanoparticles with a particle size of 50 nm in 100 mL of ethanol, sonicate for 25 min, add 0.8 parts of octadecyltrimethoxysilane (OTS), stir at 65°C for 4 h, then centrifuge, wash and dry to obtain silane-modified silica. Heat 25 parts of glyceryl monooleate (GMO) to melt, the heating temperature is 65°C, after melting, add 1 part of silane-modified silica, stir for 25 min at a speed of 800 rpm, then sonicate for 40 min, cool to room temperature to obtain a uniform modified nanocomposite; then add 2 parts of modified NCC and 0.5 parts of PIBSI / calcium borate hybrid particles prepared by Preparation Example 2, stir for 10 min, sonicate for 20 min to obtain a low-sulfur diesel oil anti-wear agent.

[0052] Example 3

[0053] Add 55 parts of sodium oleate, 5 parts of catalyst tetrabutylammonium bromide, 400 mL of solvent xylene to a three-necked flask, stir, heat to 88°C, and slowly add 45 parts of 3-chloro-1,2-propanediol dropwise, continue to heat until reflux, centrifuge at 3000 rpm for 12 min, collect the oil phase, and rotary evaporate at 65°C to obtain glyceryl monooleate (GMO).

[0054] Mix 50 parts of lignocellulose with 250 parts of 60 wt% sulfuric acid, heat to 45°C and stir magnetically for 3 hours, dilute with 2500 parts of deionized water, centrifuge at 8000 rpm for 25 min, collect the precipitate, dialyze against 12-15 kDa, freeze-dry to obtain white powder NCC, disperse in 300 parts of xylene, ultrasonic treatment for 25 min, power ≤ 200 W to prevent NCC crystal fracture, add 23 parts of lauric acid and 2.5 parts of p-toluenesulfonic acid (PTSA), heat to 112°C under nitrogen protection, reflux for 6h, cool, centrifuge at 5000 rpm for 8 min, obtain the precipitate, wash with xylene for 3 times, then wash with acetone for 3 times, remove unreacted lauric acid and p-toluenesulfonic acid, then dry at 55°C for 12h to obtain modified NCC.

[0055] Disperse 2 parts of SiO2 nanoparticles with a particle size of 50 nm in 100 mL of ethanol, ultrasonic treatment for 25 min, add 1 part of octadecyltrimethoxysilane (OTS), centrifuge after stirring at 65°C for 4h, wash and dry to obtain silane-modified silica. Heat 30 parts of glycerol monooleate (GMO) to melt, heating temperature is 65°C, after melting, add 2 parts of silane-modified silica, stir for 25 min at 800 rpm, then ultrasonic treatment for 40 min, cool to room temperature to obtain a uniform modified nanocomposite; then add 3 parts of modified NCC and 0.8 parts of PIBSI / calcium borate hybrid particles prepared by preparation example 3, stir for 10 min, ultrasonic treatment for 20 min to mix uniformly to obtain a low-sulfur diesel anti-wear agent.

[0056] Example 4

[0057] Put 60 parts of sodium oleate, 5 parts of catalyst tetrabutylammonium bromide, 400 ml of solvent xylene into a three-necked flask, stir, heat to 88°C, and slowly add 45 parts of 3-chloro-1,2-propanediol after the sodium oleate is completely dissolved. Continue to heat until reflux, centrifuge at 3000 rpm for 12 min, collect the oil phase, and rotary evaporate at 65°C to obtain glycerol monooleate (GMO).

[0058] Mix 50 parts of lignocellulose with 250 parts of 60 wt% sulfuric acid, heat to 45°C and stir magnetically for 3 hours, dilute with 2500 parts of deionized water, centrifuge at 8000 rpm for 25 min, collect the precipitate, dialyze against a 12-15 kDa molecular weight cutoff, freeze-dry to obtain white powder NCC, disperse in 300 parts of xylene, sonicate for 25 min at a power of <200 W to prevent breakage of NCC crystals, add 23 parts of lauric acid and 2.5 parts of p-toluenesulfonic acid (PTSA), heat to 112°C under nitrogen, reflux for 6 h, cool, centrifuge at 5000 rpm for 8 min, obtain the precipitate, wash with xylene 3 times, wash with acetone 3 times to remove unreacted lauric acid and p-toluenesulfonic acid, then dry at 55°C for 12 h to obtain modified NCC.

[0059] Disperse 2 parts of SiO2 nanoparticles with a particle size of 50 nm in 100 mL of ethanol, sonicate for 25 min, add 1 part of octadecyltrimethoxysilane (OTS), centrifuge after stirring at 65°C for 4 h, wash and dry to obtain silane-modified silica. Heat 30 parts of glyceryl monooleate (GMO) to melt, heat at 65°C, after melting, add 1.5 parts of silane-modified silica, stir at 800 rpm for 25 min, then sonicate for 40 min, cool to room temperature to obtain a uniform modified nanocomposite; add 3 parts of modified NCC and 1.5 parts of PIBSI / calcium borate hybrid particles prepared by Preparation Example 3, stir for 10 min, and sonicate for 20 min to obtain a low-sulfur diesel oil anti-wear agent.

[0060] Example 5

[0061] Add 60 parts of sodium oleate, 5 parts of catalyst tetrabutylammonium bromide, 400 mL of solvent xylene to a three-necked flask, stir, heat to 88°C, and slowly add 45 parts of 3-chloro-1,2-propanediol after the sodium oleate is completely dissolved, continue to heat until reflux, centrifuge at 3000 rpm for 12 min, collect the oil phase, and rotary evaporate at 65°C to obtain glyceryl monooleate (GMO).

[0062] Mix 50 parts of lignocellulose with 250 parts of 60wt% sulfuric acid, heat to 45℃ and stir magnetically for 3 hours, dilute with 2500 parts of deionized water, centrifuge at 8000 rpm for 25 min, collect the precipitate, dialyze with a molecular weight cutoff of 12-15 kDa, freeze-dry to obtain white powder NCC, disperse in 300 parts of xylene, ultrasonic treatment for 25 min, power ≤200 W to prevent NCC crystal fracture, add 23 parts of lauric acid and 2.5 parts of p-toluenesulfonic acid (PTSA), heat to 112℃ under nitrogen protection, reflux for 6h, cool, centrifuge at 5000 rpm for 8 min to obtain the precipitate, wash with xylene for 3 times, then wash with acetone for 3 times to remove unreacted lauric acid and p-toluenesulfonic acid, and then dry at 55℃ for 12h to obtain modified NCC.

[0063] Disperse 2 parts of SiO2 nanoparticles with a particle size of 50 nm in 100 mL of ethanol, ultrasonic treatment for 25 min, add 1 part of octadecyltrimethoxysilane (OTS), centrifuge after stirring at 65℃ for 4h, wash and dry to obtain silane-modified silica. Heat 30 parts of glycerol monooleate (GMO) to melt, heating temperature is 65℃, after melting, add 2 parts of silane-modified silica, stir for 25 min at 800 rpm, then ultrasonic treatment for 40 min, cool to room temperature to obtain a uniform modified nanocomposite; then add 3 parts of modified NCC and 1 part of stabilizer polyisobutylene succinimide (PIBSI), stir for 10 min, ultrasonic treatment for 20 min to mix uniformly to obtain a low-sulfur diesel anti-wear agent.

[0064] The present application also carries out comparative examples and related tests

[0065] Comparative Example 1

[0066] Compared with Example 4, the only difference is that the glycerol monooleate synthesis method commonly used in the art at present is used: glycerol and oleic acid are used as raw materials, p-toluenesulfonic acid is used as catalyst for esterification to synthesize a mixture of glycerol mono / multi-oleate instead of glycerol monooleate, and other steps and components are completely the same, to prepare a low-sulfur diesel anti-wear agent.

[0067] Comparative Example 2

[0068] Compared with Example 4, the only difference is that NCC is not modified, and NCC is directly used instead of modified NCC, and other steps and components are completely the same, to prepare a low-sulfur diesel anti-wear agent.

[0069] Comparative Example 3

[0070] Compared with Example 4, the only difference is that silica is used instead of silane-modified silica, and other steps and components are completely the same, to prepare a low-sulfur diesel anti-wear agent.

[0071] Performance test

[0072] (I) Anti-wear performance test

[0073] According to the standard GB 19147-2016 "Automotive Diesel" standard, the oil samples added with diesel anti-wear agents obtained by Examples 1-5 and Comparative Examples 1-3 were tested for lubricity by HFRR high frequency reciprocating test method, using wear scar diameter (WSD, μm) as an indicator, the additive amount was 40 ppm, the temperature was 60℃, and the test results are shown in Table 1.

[0074] (II) Low temperature flow performance test

[0075] According to the standard GB / T 510-2018 "Determination of freezing point of petroleum products" standard, the oil samples added with diesel anti-wear agents obtained by Examples 1-5 and Comparative Examples 1-3 were tested for cold filter plugging point (CFPP), the additive amount was 40 ppm, the freezing point of base diesel 0# national standard diesel was 0℃, the CFPP value (℃) was calculated and detected, and the results are shown in Table 1.

[0076] (III) Demulsification test

[0077] According to the standard ASTM D1094-00 "Determination of demulsibility of aviation fuel", the oil-water separation time of oil samples added with diesel anti-wear agents obtained by Examples 1-5 and Comparative Examples 1-3 was tested, the additive amount was 40 ppm, the base diesel 0# national standard diesel was used, the industry evaluation standard was as follows: pass: basically separated within 30 minutes, clear interface; good: most of the water was separated within 15 minutes; excellent: rapid separation within ≤5 minutes, clear interface like water. The test results are shown in Table 1.

[0078] Table 1

[0079]

[0080] From the results in Table 1, it can be seen that the diesel anti-wear agents obtained by Examples 1-5 can greatly reduce the wear scar diameter and achieve better anti-wear performance at a lower additive amount, and can significantly improve the CFPP value (℃) and the low temperature flow performance; at the same time, oil-water separation can be achieved within 15 minutes, especially the wear scar diameter of Examples 1-4 is below 323 μm, the CFPP value is improved to below -13℃, and the oil-water separation time is within 5 minutes, the anti-wear performance, low temperature flow performance and demulsification performance are all significantly improved. However, Example 5 uses PIBSI instead of PIBSI / calcium borate hybrid particles, and the anti-wear performance, low temperature flow performance and demulsification performance are all affected.

[0081] The comparative example 1 is a mixture of mono- / poly-oleic acid glycerides synthesized by traditional ester synthesis method, and the content of mono-oleic acid glyceride is low, which cannot meet the requirement of anti-wear performance (less than 460 μm) at a low additive amount (40 ppm); the comparative example 2 has poor dispersion of NCC due to no modification of NCC, which leads to a decrease in anti-wear performance; and the comparative example 3 has a relatively high CFPP value (℃) due to no use of silane-modified silica, which makes it difficult to play a role of hydrophobic nanoparticles in reducing crystallinity, thereby affecting the low-temperature flow performance.

[0082] (IV) Long-term stability test

[0083] After the oil samples added with the diesel anti-wear agents obtained in the examples 1-5 and the comparative examples 1-3 are stored for 180 days (6 months) according to the storage stability test of SH / T 0693, the appearance is observed, and the wear scar diameter is tested before and after the storage for 180 days (6 months), and the increase in wear scar diameter is calculated, and the additive amount is 40 ppm. The test results are shown in Table 2.

[0084] Table 2

[0085]

[0086] From the results in Table 2, the comparative example 2 has poor dispersion of NCC due to no modification of NCC, which leads to turbidity and precipitation, and a significant increase in wear scar diameter, and a decrease in stability; the appearance of the comparative example 3 has a slight effect, but it is not obvious, and the wear scar diameter also has a relatively large increase, and the stability is not as good as the products of the examples.

[0087] The diesel anti-wear agents obtained in the examples 1-5 can still maintain a uniform and transparent appearance without precipitation after storage for 180 days at a low additive amount, and the increase in wear scar diameter is small, and the increase is within 6 μm, which indicates that the relative long-term stability can be maintained.

[0088] The above is the preferred embodiment of the present application, and for those skilled in the art, some improvements and refinements made without departing from the principles of the present application should also be considered as the protection scope of the present application.

Claims

1. A process for the preparation of a low sulphur diesel anti-wear agent characterised in that: The method comprises the following steps: S1. Sodium oleate, tetrabutylammonium bromide and xylene are added into a three-necked flask, stirred and mixed, heated, 3-chloro-1,2-propanediol is added dropwise, and the temperature is continuously increased until reflux, centrifuged, and rotary evaporated to obtain glycerol monooleate; S2. The NCC is dispersed in xylene, lauric acid and p-toluenesulfonic acid are added, heated under the protection of inert atmosphere, and refluxed to react, cooled, centrifuged, washed, and dried to obtain modified NCC; S3. The glycerol monooleate is heated and melted, the silane-modified silicon dioxide is added, stirred, ultrasonically treated, and cooled to obtain modified nanocomposites, and then the modified NCC and the stabilizer are added, and the mixture is stirred and ultrasonically treated to obtain the low-sulfur diesel oil anti-wear agent. The stabilizer is PIBSI / calcium borate hybrid particles obtained by hybridizing PIBSI with calcium borate; it is prepared by the following method: dissolving PIBSI and Span-80 in n-heptane to obtain an oil phase, adding part of the oil phase to a calcium nitrate solution, shearing to obtain a microemulsion with Ca 2+ encapsulated therein; adding the remaining oil phase to a borax solution, shearing to obtain a microemulsion with B4O7 2- encapsulated therein, mixing with the microemulsion with Ca 2+ encapsulated therein, heating, stirring to react, adding acetone to demulsify, centrifuging, washing, vacuum drying to obtain PIBSI / calcium borate hybrid particles.

2. A process for the preparation of a low sulphur diesel anti-wear agent according to claim 1, characterized in that: The PIBSI / calcium borate hybrid particles were prepared by shearing at 8000-10000 rpm for 15 min after adding the microemulsion encapsulating Ca 2+ The PIBSI / calcium borate hybrid particles were prepared by shearing at 8000-10000 rpm for 15 min after adding the microemulsion encapsulating Ca The calcium nitrate solution was prepared by dissolving 10-15 parts of calcium nitrate in 100 parts of deionized water; The borax solution is prepared by dissolving 13-19 parts of borax in 100 parts of deionized water.

3. A process for the preparation of a low sulphur diesel anti-wear agent as claimed in claim 1, wherein: The NCC is prepared by the following method: wood fibers are mixed with 60 wt% sulfuric acid at a mass ratio of 1:5, the temperature is increased to 45°C, and magnetic stirring is performed for 3 hours, deionized water is added for dilution, centrifugation is performed at 8000 rpm for 25 min, the precipitate is collected, dialysis is performed with a molecular weight cutoff of 12-15 kDa, and freeze-drying is performed to obtain the NCC.

4. A process for the preparation of a low sulphur diesel anti-wear agent as claimed in claim 1, wherein: The silane-modified silicon dioxide is prepared by dispersing SiO2 nanoparticles with a particle size of 50 nm in ethanol, ultrasonically treating for 25 min, adding octadecyltrimethoxysilane, stirring and reacting at 65°C for 4 h, and then centrifuging, washing, and drying to obtain the silane-modified silicon dioxide.

5. A process for the preparation of a low sulphur diesel anti-wear agent as claimed in claim 1, wherein: In the step S1, the temperature is heated to 88°C, the sodium oleate is completely dissolved, 3-chloro-1,2-propanediol is slowly added dropwise, the temperature is continuously increased until reflux, 3000 rpm centrifugation is performed for 12 min, the oil phase is collected, and rotary evaporation is performed at 55-65°C to obtain glycerol monooleate; In the step S2, the NCC is dispersed in xylene, ultrasonically treated for 25 min, lauric acid and p-toluenesulfonic acid are added, heated to 112°C under the protection of nitrogen, and refluxed to react for 6 h, cooled, centrifuged at a speed of 5000 rpm for 8 min to obtain a precipitate, washed with xylene for 3 times, washed with acetone for 3 times, and then dried at 55°C for 12 h to obtain the modified NCC.

6. A process for the preparation of a low sulphur diesel anti-wear agent as claimed in claim 1, wherein: In the step S3, the temperature for heating and melting the glycerol monooleate is 65°C, the silane-modified silicon dioxide is added after melting, stirred for 25 min at a speed of 800 rpm, ultrasonically treated for 40 min, and then cooled to room temperature to obtain the modified nanocomposites, the modified NCC and the stabilizer are added, stirred for 10 min, and ultrasonically treated for 20 min to obtain the low-sulfur diesel oil anti-wear agent.

7. A process for the preparation of a low sulphur diesel anti-wear agent according to any one of claims 1 to 6, characterised in that: The low-sulfur diesel oil anti-wear agent comprises the following substances in the following mass fractions: 20-30 parts of glycerol monooleate, 0.5-2 parts of silane-modified silicon dioxide, 1-3 parts of modified NCC, and 0.5-1.5 parts of stabilizer.

8. A process for the preparation of a low sulphur diesel anti-wear agent as claimed in claim 1, wherein: The single oleic acid glyceride comprises the following mass parts of raw materials: 30-60 parts of sodium oleate, 2-5 parts of tetrabutylammonium bromide, 300-400 parts of dimethylbenzene, 22-45 parts of 3-chloro-1,2-propanediol; the modified NCC comprises the following mass parts of raw materials: 30-50 parts of wood fiber, 150-250 parts of sulfuric acid with a concentration of 60wt%, 200-300 parts of dimethylbenzene, 15-23 parts of lauric acid and 1.5-2.5 parts of p-toluenesulfonic acid; the silane modified silicon dioxide comprises the following mass parts of raw materials: 1-2 parts of SiO2, 0.5-1 part of octadecyltrimethoxysilane; the stabilizer is PIBSI / calcium borate hybrid particles, comprising the following mass parts of raw materials: 10-15 parts of calcium nitrate, 13-19 parts of borax, 13-20 parts of PIBSI, 1.2-2 parts of Span-80, 400-500 parts of n-heptane. 10-15 parts of calcium nitrate, 13-19 parts of borax, 13-20 parts of PIBSI, 1.2-2 parts of Span-80, 400-500 parts of n-heptane.

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