A gasoline antiknock agent and its preparation method and application

Abstract

This invention proposes a gasoline antiknock agent, its preparation method, and its application, belonging to the field of antiknock agent technology. Palm oil is subjected to molecular distillation, and the secondary distillation product and undistilled substances are collected. The undistilled substances react with ethanol to obtain palm oil fatty acid ethyl esters. The secondary distillation product undergoes a saponification reaction with an alkali to obtain a saponified product, which is then added to water with a hydrophilic emulsifier to obtain an aqueous phase. A lipophilic emulsifier, methyl malonate, and palm oil fatty acid ethyl esters are added to the residual oil to obtain an oil phase. The aqueous phase is then added dropwise to the oil phase, emulsified, and filtered to obtain the gasoline antiknock agent. This gasoline antiknock agent achieves antiknock through the rapid vaporization of nano-water droplets. While providing antiknock protection, it also reduces cylinder temperature and exhaust emissions. Furthermore, its components are safe and environmentally friendly, non-polluting, non-toxic, easily degradable, and low-cost. It maintains good antiknock performance even at relatively low temperatures, indicating broad application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of antiknock agents, and in particular to a gasoline antiknock agent and a preparation method and application thereof. Background Art

[0002] Gasoline antiknock agents are divided into metal antiknock agents and non-metal antiknock agents. Commonly used metal antiknock agents include tetraethyl lead (TEL), ferrocene, and methylcyclopentadiene tricarbonyl manganese (MMT). Although they can effectively improve the antiknock performance of gasoline, they have residual problems after long-term use, which can cause problems such as engine spark plug blockage and cylinder wear, and health hazards caused by human contact. As the world's requirements for the environment are getting higher and higher, it is expressly prohibited to add metal antiknock agents containing lead and iron compounds. Aniline and its derivative antiknock agents are also highly toxic compounds. At the same time, the combustion products contain a large amount of nitrogen oxides, which affect other indicators of gasoline and pollute the atmosphere. Therefore, the development of new non-metallic ashless gasoline antiknock agents is a topic that the world is working hard on. Summary of the invention

[0003] The purpose of the present invention is to propose a gasoline antiknock agent and its preparation method and application, which realizes antiknock through the rapid vaporization of nano water droplets, and can reduce the cylinder temperature, reduce exhaust gas emissions, and inhibit the combustion rate while preventing explosion. Unsaturated hydrocarbons are converted into epoxy compounds during the accelerated combustion period, and the probability of flame center generation in the unburned zone is reduced. The antiknock agent structure contains many oxygen atoms, which can make the combustion more complete and thorough. The ingredients are safe and environmentally friendly, do not pollute the environment, are non-toxic, easily degradable, and have low cost. They still maintain good antiknock performance at lower temperatures, and have broad application prospects.

[0004] The technical solution of the present invention is achieved in this way:

[0005] The present invention provides a method for preparing a gasoline antiknock agent, comprising the following steps:

[0006] S1. Molecular distillation: Add palm oil to a molecular distillation device, heat to 150-170℃ for distillation, remove the primary distillation product, increase the temperature to 180-200℃ for distillation, collect the secondary distillation product, and retain the undistilled material;

[0007] S2. Preparation of palm oil fatty acid ethyl ester: the undistilled substance is subjected to an ethyl esterification reaction with anhydrous ethanol under the action of a catalyst to obtain palm oil fatty acid ethyl ester; the mass ratio of the undistilled substance to anhydrous ethanol is 10:2-3;

[0008] S3. Saponification reaction: adding the secondary distillation product to an alkali solution, adding a catalyst, heating and stirring the reaction, volatilizing the solvent, filtering, washing, and drying to obtain a saponification product; the mass ratio of the secondary distillation product, the alkali solution and the catalyst is 1:10-15:0.01-0.02;

[0009] S4. Preparation of an aqueous phase: adding a hydrophilic emulsifier to water, adding a saponification product, stirring and mixing to obtain an aqueous phase; the mass ratio of the hydrophilic emulsifier, the saponification product and water is 1-2:2-3:50;

[0010] The hydrophilic emulsifier is selected from at least one of Tween-20, Tween-40, Tween-60, Tween-80 and Tween-85;

[0011] S5. Preparation of the oil phase: adding a lipophilic emulsifier to the residue oil, adding methyl malonate and palm oil fatty acid ethyl ester, stirring and mixing to obtain an oil phase; the mass ratio of the lipophilic emulsifier, methyl malonate, palm oil fatty acid ethyl ester and the residue oil is 3-5:4-6:3-5:100;

[0012] The lipophilic emulsifier is selected from at least one of Span-20, Span-40, Span-60, Span-80 and Span-85;

[0013] S6. Preparation of gasoline antiknock agent: add water phase to the oil phase, emulsify, filter, and obtain gasoline antiknock agent.

[0014] As a further improvement of the present invention, the distillation condensation temperature of the molecular distillation in step S1 is 2-5°C, the scraping speed is 150-250r / min, the feed flow rate is 3-5mL / min, and the system vacuum degree is 50-70Pa.

[0015] As a further improvement of the present invention, the catalyst in step S2 is NaOH or KOH, the added amount of the catalyst is 2-3wt% of the undistilled material, the reaction temperature is 60-80°C, and the reaction time is 2-3h.

[0016] As a further improvement of the present invention, the mass ratio of the secondary distillation product, alkali solution and catalyst in step S3 is 1:10-15:0.01-0.02, the alkali solution is 20-25wt% NaOH or KOH solution, the catalyst is hexadecyltrimethylammonium bromide, the temperature of the heating and stirring reaction is 40-50°C, and the time is 30-40min.

[0017] As a further improvement of the present invention, the emulsification speed in step S6 is 10000-12000 r / min, and the time is 15-25 min.

[0018] The present invention further protects a gasoline antiknock agent prepared by the above preparation method.

[0019] The present invention further protects the use of the gasoline antiknock agent in improving the octane number of gasoline.

[0020] The present invention has the following beneficial effects:

[0021] When the gasoline octane number matches the engine compression ratio, the mixture of gasoline vapor and air is compressed in the cylinder, and its temperature rises. Once ignited by the electric spark, it ignites and burns layer by layer with the spark plug as the center, and spreads smoothly to the unburned area. At this time, the temperature and pressure in the cylinder change evenly, and the engine works normally. When using low-octane gasoline, a large amount of unstable peroxides have been formed in the mixture in the place where the flame front has not yet spread, and spontaneous combustion forms multiple combustion centers. The shock waves generated collide with each other, violently hit the piston head and cylinder, and make a metallic knocking sound, which is the detonation phenomenon. The role of the anti-knock agent is to react with the active substances of the flame front reaction, destroy the peroxide, change the reaction path, and prolong the reaction induction period. The anti-knock agent plays an anti-catalytic role, limiting the fuel combustion to the normal combustion range, that is, before the flame front arrives, suppress the spontaneous combustion of the fuel, or achieve the purpose of anti-knock by increasing the flame propagation speed.

[0022] Palm oil has the following advantages as an anti-knock agent: it is a renewable energy source; it can be degraded by microorganisms, and the degradation rate is more than twice that of gasoline; it can significantly reduce the emission of CO and hydrocarbons in the combustion exhaust. However, it has the following disadvantages: it has poor low temperature resistance and cannot be used in the winter in the north, mainly because its low-boiling solid acid substances are difficult to dissolve in gasoline at low temperatures. The present invention adopts a molecular distillation method to remove the low-boiling primary distillation product, collect the medium-boiling secondary distillation product, and the high-boiling palm oil part is the undistilled substance.

[0023] Under the action of catalyst, the high-boiling-point undistilled substances react with ethanol for esterification, and have excellent lubricity, higher cetane number, low toxicity and lower condensation point. They are derived from biomass and are biodegradable, have good anti-knock performance, fast combustion speed and high combustion calorific value. Methyl malonate additive can greatly improve the octane number of gasoline, and will not increase engine wear, nor cause exhaust gas poisoning. Adding water will not cause phase separation, and it can also improve the low-temperature solubility of palm oil to a certain extent. Palm oil fatty acid ethyl ester, methyl malonate and lipophilic emulsifier are mixed to prepare the oil phase; the secondary distillation product with medium boiling point reacts with alkali for saponification under the action of catalyst, and the generated saponification product has good surface activity and can synergize with hydrophilic surfactant to form water phase; the water phase is added dropwise to the oil phase, and emulsified at high speed to form a nano-scale oil-in-water emulsion, which can reduce the cylinder temperature and exhaust gas emissions while resisting explosion, and the anti-knock purpose is achieved through the rapid vaporization of nano water droplets.

[0024] The gasoline antiknock agent of the present invention can achieve antiknock through the rapid vaporization of nano water droplets. At the same time, it can reduce the cylinder temperature, reduce exhaust gas emissions, and inhibit the combustion speed. In the accelerated combustion period, unsaturated hydrocarbons are converted into epoxy compounds, and the probability of the formation of flame centers in the unburned area is reduced. The antiknock agent structure contains many oxygen atoms, which can make the combustion more complete and thorough. The ingredients are safe and environmentally friendly, do not pollute the environment, are non-toxic, easily degradable, and have low cost. It still maintains good antiknock performance at a relatively low temperature, and has broad application prospects. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0026] This embodiment provides a method for preparing a gasoline antiknock agent, comprising the following steps:

[0027] S1. Molecular distillation: Add palm oil to the molecular distillation device, heat to 150℃ for distillation, remove the primary distillation product, increase the temperature to 180℃ for distillation, collect the secondary distillation product, and retain the undistilled material;

[0028] The distillation condensation temperature is 2°C, the scraping speed is 150r / min, the feed flow rate is 3mL / min, and the system vacuum is 50Pa;

[0029] S2. Preparation of palm oil fatty acid ethyl ester: 10 g of the undistilled material was mixed with 2 g of anhydrous ethanol under the action of NaOH, the catalyst was added in an amount of 2 wt% of the undistilled material, heated to 60°C, stirred for reaction for 2 h, an equal volume of petroleum ether was added, washed with 5 wt% NaCl solution, the organic layer was collected, and the solvent was removed under reduced pressure to obtain palm oil fatty acid ethyl ester;

[0030] S3. Saponification reaction: 10 g of the secondary distillation product was added to 100 g of a 20 wt% NaOH solution, 0.1 g of hexadecyltrimethylammonium bromide was added, the mixture was heated to 40 ° C, the reaction was stirred for 30 min, the solvent was evaporated, filtered, washed, and dried to obtain a saponification product;

[0031] S4 Preparation of the aqueous phase: 1g Tween-40 was added to 50g of water, 2g of the saponification product was added, and the mixture was stirred to obtain an aqueous phase;

[0032] S5 Preparation of the oil phase: 3g Span -40 was added to 100g of residue oil, 4g of methyl malonate, 3g of palm oil fatty acid ethyl ester was added, and the mixture was stirred to obtain an oil phase;

[0033] S6. Preparation of gasoline antiknock agent: add water phase dropwise to the oil phase, emulsify at 10000r / min for 15min, filter, and obtain gasoline antiknock agent. Example 2

[0034] This embodiment provides a method for preparing a gasoline antiknock agent, comprising the following steps:

[0035] S1. Molecular distillation: Add palm oil to the molecular distillation device, heat to 170℃ for distillation, remove the primary distillation product, increase the temperature to 200℃ for distillation, collect the secondary distillation product, and retain the undistilled material;

[0036] The distillation condensation temperature is 5°C, the scraping speed is 250r / min, the feed flow rate is 5mL / min, and the system vacuum is 70Pa;

[0037] S2. Preparation of palm oil fatty acid ethyl ester: 10 g of the undistilled material was mixed with 3 g of anhydrous ethanol under the action of KOH, the catalyst was added in an amount of 3 wt % of the undistilled material, heated to 80° C., stirred for reaction for 3 h, an equal volume of petroleum ether was added, washed with 5 wt % NaCl solution, the organic layer was collected, and the solvent was removed under reduced pressure to obtain palm oil fatty acid ethyl ester;

[0038] S3. Saponification reaction: 10 g of the secondary distillation product was added to 150 g of a 25 wt% KOH solution, 0.2 g of hexadecyltrimethylammonium bromide was added, the mixture was heated to 50 ° C, the reaction was stirred for 40 min, the solvent was evaporated, filtered, washed, and dried to obtain a saponification product;

[0039] S4 Preparation of the aqueous phase: 2g Tween-80 was added to 50g of water, 3g of the saponification product was added, and the mixture was stirred to obtain an aqueous phase;

[0040] S5 Preparation of the oil phase: 5g Span -80 was added to 100g of residue oil, 6g of methyl malonate, 5g of palm oil fatty acid ethyl ester was added, and the mixture was stirred to obtain an oil phase;

[0041] S6. Preparation of gasoline antiknock agent: add water phase dropwise to the oil phase, emulsify at 12000r / min for 25min, filter, and obtain gasoline antiknock agent. Example 3

[0042] This embodiment provides a method for preparing a gasoline antiknock agent, comprising the following steps:

[0043] S1. Molecular distillation: Add palm oil to the molecular distillation device, heat to 160℃ for distillation, remove the primary distillation product, increase the temperature to 190℃ for distillation, collect the secondary distillation product, and retain the undistilled material;

[0044] The distillation condensation temperature was 3°C, the scraping speed was 200 r / min, the feed flow rate was 4 mL / min, and the system vacuum was 60 Pa;

[0045] S2. Preparation of palm oil fatty acid ethyl ester: 10 g of the undistilled material was mixed with 2.5 g of anhydrous ethanol under the action of NaOH, the catalyst was added in an amount of 2.5 wt% of the undistilled material, heated to 70°C, stirred for reaction for 2.5 h, an equal volume of petroleum ether was added, washed with 5 wt% NaCl solution, the organic layer was collected, and the solvent was removed under reduced pressure to obtain palm oil fatty acid ethyl ester;

[0046] S3. Saponification reaction: 10 g of the secondary distillation product was added to 120 g of a 22 wt% KOH solution, 0.15 g of hexadecyltrimethylammonium bromide was added, the mixture was heated to 45 ° C, the reaction was stirred for 35 min, the solvent was evaporated, filtered, washed, and dried to obtain a saponification product;

[0047] S4 Preparation of the aqueous phase: 1.5g of Tween-85 was added to 50g of water, 2.5g of the saponification product was added, and the mixture was stirred to obtain an aqueous phase;

[0048] S5 Preparation of the oil phase: 4g Span -85 was added to 100g of residue oil, 5g of methyl malonate, 4g of palm oil fatty acid ethyl ester was added, and the mixture was stirred to obtain an oil phase;

[0049] S6. Preparation of gasoline antiknock agent: add water phase dropwise to the oil phase, emulsify at 11000r / min for 20min, filter, and obtain gasoline antiknock agent.

[0050] Comparative Example 1

[0051] Compared with Example 3, the difference is that step S1 is not performed.

[0052] The details are as follows:

[0053] S1. Preparation of palm oil fatty acid ethyl ester: 10 g of palm oil was mixed with 2.5 g of anhydrous ethanol under the action of NaOH, the catalyst was added in an amount of 2.5 wt% of the undistilled material, heated to 70°C, stirred for reaction for 2.5 h, an equal volume of petroleum ether was added, washed with 5 wt% NaCl solution, the organic layer was collected, and the solvent was removed under reduced pressure to obtain palm oil fatty acid ethyl ester;

[0054] S2. Saponification reaction: 10 g of palm oil was added to 120 g of 22 wt% KOH solution, 0.15 g of hexadecyltrimethylammonium bromide was added, the mixture was heated to 45 ° C, stirred for 35 min, the solvent was evaporated, filtered, washed, and dried to obtain a saponification product;

[0055] S3 Preparation of the aqueous phase: 1.5g of Tween-85 was added to 50g of water, 2.5g of the saponification product was added, and the mixture was stirred to obtain an aqueous phase;

[0056] S4 Preparation of the oil phase: 4g Span -85 was added to 100g of residue oil, 5g of methyl malonate, 4g of palm oil fatty acid ethyl ester was added, and the mixture was stirred to obtain an oil phase;

[0057] S5. Preparation of gasoline antiknock agent: add water phase dropwise to the oil phase, emulsify at 11000r / min for 20min, filter, and obtain gasoline antiknock agent.

[0058] Comparative Example 2

[0059] Compared with Example 3, the difference is that step S2 is not performed.

[0060] The details are as follows:

[0061] S1. Molecular distillation: Add palm oil to the molecular distillation device, heat to 160℃ for distillation, remove the primary distillation product, increase the temperature to 190℃ for distillation, collect the secondary distillation product, and retain the undistilled material;

[0062] The distillation condensation temperature was 3°C, the scraping speed was 200 r / min, the feed flow rate was 4 mL / min, and the system vacuum was 60 Pa;

[0063] S2. Saponification reaction: 10 g of the secondary distillation product was added to 120 g of a 22 wt% KOH solution, 0.15 g of hexadecyltrimethylammonium bromide was added, the mixture was heated to 45 ° C, stirred for 35 min, the solvent was evaporated, filtered, washed, and dried to obtain a saponification product;

[0064] S3 Preparation of the aqueous phase: 1.5g of Tween-85 was added to 50g of water, 2.5g of the saponification product was added, and the mixture was stirred to obtain an aqueous phase;

[0065] S4 Preparation of the oil phase: 4g Span -85 was added to 100g of residual oil, 5g of methyl malonate, 4g of undistilled material was added, and stirred to mix well to obtain an oil phase;

[0066] S5. Preparation of gasoline antiknock agent: add water phase to the oil phase, emulsify at 11000r / min for 20min, filter, and obtain gasoline antiknock agent

[0067] Comparative Example 3

[0068] Compared with Example 3, the difference is that step S3 is not performed.

[0069] The details are as follows:

[0070] S1. Molecular distillation: Add palm oil to the molecular distillation device, heat to 160℃ for distillation, remove the primary distillation product, increase the temperature to 190℃ for distillation, collect the secondary distillation product, and retain the undistilled material;

[0071] The distillation condensation temperature was 3°C, the scraping speed was 200 r / min, the feed flow rate was 4 mL / min, and the system vacuum was 60 Pa;

[0072] S2. Preparation of palm oil fatty acid ethyl ester: 10 g of the undistilled material was mixed with 2.5 g of anhydrous ethanol under the action of NaOH, the catalyst was added in an amount of 2.5 wt% of the undistilled material, heated to 70°C, stirred for reaction for 2.5 h, an equal volume of petroleum ether was added, washed with 5 wt% NaCl solution, the organic layer was collected, and the solvent was removed under reduced pressure to obtain palm oil fatty acid ethyl ester;

[0073] S3 Preparation of the aqueous phase: 1.5g Tween-85 was added to 50g of water, 2.5g of the secondary distillation product was added, and the mixture was stirred to obtain an aqueous phase;

[0074] S4 Preparation of the oil phase: 4g Span -85 was added to 100g of residue oil, 5g of methyl malonate, 4g of palm oil fatty acid ethyl ester was added, and the mixture was stirred to obtain an oil phase;

[0075] S5. Preparation of gasoline antiknock agent: add water phase dropwise to the oil phase, emulsify at 11000r / min for 20min, filter, and obtain gasoline antiknock agent.

[0076] Comparative Example 4

[0077] Compared with Example 3, the difference is that no saponification product is added in step S4.

[0078] The details are as follows:

[0079] S4. Preparation of aqueous phase: Add 1.5 g of Tween-85 to 50 g of water, stir and mix well to prepare an aqueous phase.

[0080] Comparative Example 5

[0081] Compared with Example 3, the difference is that Tween-85 is not added in step S4.

[0082] The details are as follows:

[0083] S4. Preparation of aqueous phase: Add 2.5 g of the saponification product to 50 g of water, stir and mix well to obtain an aqueous phase.

[0084] Comparative Example 6

[0085] Compared with Example 3, the difference is that palm oil fatty acid ethyl ester is not added in step S5.

[0086] The details are as follows:

[0087] S5. Preparation of oil phase: 4 g of Span-85 was added to 100 g of residual oil, and 9 g of methyl malonate was added, and the mixture was stirred and mixed to obtain an oil phase.

[0088] Comparative Example 7

[0089] Compared with Example 3, the difference is that methyl malonate is not added in step S5.

[0090] The details are as follows:

[0091] S5. Preparation of oil phase: 4 g of Span-85 was added to 100 g of residual oil, and 9 g of palm oil fatty acid ethyl ester was added, and the mixture was stirred and mixed to obtain an oil phase.

[0092] Comparative Example 8

[0093] Compared with Example 3, the difference is that Span-85 is not added in step S5.

[0094] The details are as follows:

[0095] S5. Preparation of oil phase: 5 g of methyl malonate and 4 g of palm oil fatty acid ethyl ester were added to 100 g of residual oil, and the mixture was stirred and mixed to obtain an oil phase.

[0096] Test Example 1

[0097] The gasoline antiknock agents prepared in Examples 1-3 and Comparative Examples 1-8 were added to No. 92 gasoline in an amount of 2 vol%. The test process of the research octane number (RON) was carried out in accordance with GB / T5487-2015, and the test process of the motor octane number (MON) was carried out in accordance with GB / T503-2016. The results are shown in Table 1.

[0098] Table 1 ;

[0099] It can be seen from the above table that the gasoline antiknock agents prepared in Examples 1-3 of the present invention can significantly increase the octane number of gasoline.

[0100] Test Example 2

[0101] Using catalytic cracking gasoline as the base oil, according to the method of GB / T 5096-85, a copper sheet with a purity of >99.15% was suspended and immersed in the gasoline antiknock agent base oil with a mass fraction of 2 vol% prepared in Examples 1-3 and Comparative Examples 1-8 for 2 h. The results are shown in Table 2.

[0102] Table 2 ;

[0103] "Petroleum Products Copper Strip Corrosion Test Method" is graded according to the corrosion standard color plate, 1a means: Level 1 mild discoloration, a is light orange, almost the same as a newly polished copper strip; b is dark orange.

[0104] It can be seen from the above table that the gasoline antiknock agents prepared in Examples 1-3 of the present invention have low corrosiveness.

[0105] Test Example 3

[0106] The gasoline antiknock agents prepared in Examples 1-3 and Comparative Examples 1-8 were added to No. 92 gasoline in an amount of 2 vol%. The starting time at -10°C was tested. The results are shown in Table 3.

[0107] Table 3 ;

[0108] It can be seen from the above table that the gasoline antiknock agents prepared in Examples 1-3 of the present invention still maintain good performance at low temperatures.

[0109] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a gasoline antiknock agent, characterized in that: The following steps are involved: S1. Molecular distillation: Add palm oil to a molecular distillation device, heat to 150-170℃ for distillation, remove the primary distillation product, increase the temperature to 180-200℃ for distillation, collect the secondary distillation product, and retain the undistilled material; S2. Preparation of palm oil fatty acid ethyl ester: the undistilled substance is subjected to an ethyl esterification reaction with anhydrous ethanol under the action of a catalyst to obtain palm oil fatty acid ethyl ester; the mass ratio of the undistilled substance to anhydrous ethanol is 10:2-3; S3. Saponification reaction: adding the secondary distillation product to an alkali solution, adding a catalyst, heating and stirring the reaction, volatilizing the solvent, filtering, washing, and drying to obtain a saponification product; the mass ratio of the secondary distillation product, the alkali solution and the catalyst is 1:10-15:0.01-0.02; S4. Preparation of an aqueous phase: adding a hydrophilic emulsifier to water, adding a saponification product, stirring and mixing to obtain an aqueous phase; the mass ratio of the hydrophilic emulsifier, the saponification product and water is 1-2:2-3:50; The hydrophilic emulsifier is selected from at least one of Tween-20, Tween-40, Tween-60, Tween-80 and Tween-85; S5. Preparation of the oil phase: adding a lipophilic emulsifier to the residue oil, adding methyl malonate and palm oil fatty acid ethyl ester, stirring and mixing to obtain an oil phase; the mass ratio of the lipophilic emulsifier, methyl malonate, palm oil fatty acid ethyl ester and the residue oil is 3-5:4-6:3-5:100; The lipophilic emulsifier is selected from at least one of Span-20, Span-40, Span-60, Span-80 and Span-85; S6. Preparation of gasoline antiknock agent: add water phase to the oil phase, emulsify, filter, and obtain gasoline antiknock agent.

2. The preparation method according to claim 1, characterized in that: The distillation condensation temperature of the molecular distillation in step S1 is 2-5°C, the scraping speed is 150-250r / min, the feed flow rate is 3-5mL / min, and the system vacuum degree is 50-70Pa.

3. The preparation method according to claim 1, characterized in that: In step S2, the catalyst is NaOH or KOH, the amount of the catalyst added is 2-3wt% of the undistilled material, the reaction temperature is 60-80°C, and the reaction time is 2-3h.

4. The preparation method according to claim 1, characterized in that: In step S3, the alkali solution is a 20-25wt% NaOH or KOH solution, the catalyst is hexadecyltrimethylammonium bromide, the temperature of the heating and stirring reaction is 40-50°C, and the time is 30-40min.

5. The preparation method according to claim 1, characterized in that: The emulsification speed in step S6 is 10000-12000 r / min, and the time is 15-25 min.

6. A gasoline antiknock agent obtained by the preparation method according to any one of claims 1 to 5.

7. Use of the gasoline antiknock agent as claimed in claim 6 in improving the octane number of gasoline.