A fuel detergent composition and a method for its preparation

Abstract

The present application relates to the technical field of fuel additive, in particular to a fuel detergent composition and a preparation method thereof.The composition comprises 90-110 parts of gradient polyether amine main detergent molecules, 70-90 parts of aromatic hydrocarbon solvent oil and 1-3 parts of 2,6-di-tert-butyl-p-cresol by mass fraction.The gradient polyether amine main detergent molecules have a gradient structure of polyisobutylene-polyoxypropylene-polyoxyethylene-primary amine, and the key to its preparation is to first obtain a monohydroxyl intermediate by borohydride-oxidation of high-reactivity polyisobutylene, then sequentially perform ring-opening polymerization with propylene oxide and ethylene oxide added twice in turn, and finally introduce a terminal primary amine by catalytic amination.The composition can significantly reduce the intake valve deposits, effectively clean and restore the in-cylinder direct injection fuel injector flow, improve the fuel atomization uniformity, and has good low-temperature gasoline compatibility and high-temperature stability.

Description

Technical Field

[0001] This invention relates to the field of fuel additive technology, and in particular to a fuel detergent composition and its preparation method. Background Technology

[0002] With the continuous advancement of engine technology, especially the widespread application of direct injection and turbocharging, the operating environment of fuel systems is becoming increasingly demanding. Under high temperature and high pressure conditions, unsaturated hydrocarbons and trace impurities in the fuel are prone to oxidation and polymerization on the surfaces of critical components such as intake valves and injectors, forming stubborn deposits. These deposits can disrupt fuel spray patterns, affect the air-fuel ratio, and lead to decreased engine power, increased fuel consumption, and worsened emissions. Currently, commercially available fuel additives generally use polyetheramine (PEA) or polyisobutyleneamine (PIBA) as the main detergent, which adsorbs and disperses deposits through their polar groups.

[0003] However, traditional polyetheramines have relatively simple molecular structures, and their lipophilic polyether segments and hydrophilic amine groups have limitations in their dissolution and diffusion behavior in fuel, as well as their ability to target and clean deposits in different temperature ranges. For example, while some additives can effectively inhibit the formation of deposits in low-temperature zones (such as intake valves), their cleaning and restoration effects on carbon deposits already formed in high-temperature zones (such as needle valves of direct injection fuel injectors) are limited. Some high-molecular-weight products, while exhibiting good retention in high-temperature zones, may lead to poor low-temperature fluidity and incompatible gasoline, potentially precipitating in cold environments and even clogging fuel filters. Furthermore, in conventional polyetheramine synthesis processes, the addition method of epoxides (such as one-time mixing) makes it difficult to precisely control the polarity distribution and gradient at the ends of the molecular chains, resulting in insufficient directional adsorption and penetration on metal or carbon deposit surfaces, affecting their cleaning efficiency and durability.

[0004] Existing technologies also attempt to improve the molecular structure, such as introducing polyisobutylene segments to enhance oil solubility or modifying amine groups. However, these improvements often address one aspect at the expense of another, failing to systematically solve the balance between the molecular's dispersion stability in fuel, its broad affinity for deposit surfaces, its persistent adsorption on high-temperature surfaces, and its rapid cleaning and recovery capabilities. Especially for direct injection engines, the high temperatures inside the injector can easily cause detergent molecules to thermally decompose or fail before they can exert their cleaning effect. Therefore, designing a fuel detergent molecular structure that combines excellent low-temperature compatibility, high-temperature stability, and efficient cleaning and repair capabilities has become a critical technological bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a fuel detergent composition and its preparation method, so as to solve the problem that existing fuel detergents have a single molecular structure and are difficult to simultaneously achieve excellent low-temperature gasoline compatibility, high-temperature stability, and efficient cleaning and repair capabilities for low-temperature deposits in the intake system and high-temperature carbon deposits in the direct injection system.

[0006] To achieve the above objectives, the present invention provides a fuel detergent composition comprising, by weight, 90-110 parts of graded polyetheramine main detergent molecules, 70-90 parts of aromatic solvent oil and 1-3 parts of 2,6-di-tert-butyl-p-cresol;

[0007] The gradient polyetheramine main cleaning molecule is obtained by hydroboration and oxidation of highly reactive polyisobutylene to form a monohydroxy polyisobutylene intermediate, followed by the sequential introduction of polyoxypropylene segments and polyoxyethylene enrichment segments at the end of the chain and the subsequent end-amination.

[0008] The gradient polyetheramine main cleaning molecule has a single-sided polyisobutylene end group, a polyoxypropylene segment located between the single-sided polyisobutylene end group and the end-chain polyoxyethylene enrichment segment, and a terminal primary amine adjacent to the end-chain polyoxyethylene enrichment segment.

[0009] The chain-end polyoxyethylene enrichment segment is formed by adding ethylene oxide in two separate steps after the residual amount of propylene oxide is less than 2 g / kg.

[0010] The gradient polyetheramine main cleaning molecules have a number average molecular weight of 1300-1600 and a total amine value of 35-44 mg KOH / g.

[0011] Preferably, the highly reactive polyisobutylene has a number average molecular weight of 1000 and a molar content of terminal vinylidene double bonds of 87.4%.

[0012] Preferably, the monohydroxy polyisobutylene intermediate is obtained by reacting 180-220 parts of highly reactive polyisobutylene, 108-132 parts of a 2 mol / L solution of borane dimethyl sulfide complex tetrahydrofuran, 14-18 parts of sodium hydroxide, 126-150 parts of deionized water, and 90-110 parts of a 30% hydrogen peroxide solution in 360-440 parts of anhydrous n-hexane.

[0013] Preferably, by mass parts, the gradient polyetheramine main cleaning molecule is obtained by ring-opening reaction of 140-160 parts of monohydroxy polyisobutylene intermediate, 32-48 parts of propylene oxide, 3-5 parts of the first part of ethylene oxide and 6-10 parts of the second part of ethylene oxide to form a gradient polyether alcohol intermediate, followed by catalytic amination; the number average molecular weight of the gradient polyether alcohol intermediate is 1300-1600 and the hydroxyl value is 36-43 mg KOH / g.

[0014] Preferably, the ring-opening reaction comprises: forming a polyisobutylene alkoxide starting seed by reacting the monohydroxy polyisobutylene intermediate with 35-45 parts anhydrous toluene, 15-25 parts anhydrous tetrahydrofuran, 4-6 parts 18-crown ether-6 and 1.5-2.5 parts potassium tert-butoxide; adding propylene oxide to the polyisobutylene alkoxide starting seed and reacting until the residual propylene oxide is less than 2 g / kg; adding a first part of ethylene oxide and reacting until the residual ethylene oxide is less than 2 g / kg; adding a second part of ethylene oxide and reacting until the residual ethylene oxide is less than 2 g / kg; and finally adding 1.5-2.5 parts of glacial acetic acid to neutralize, thereby obtaining a gradient polyether alcohol intermediate.

[0015] Preferably, in the catalytic amination, based on 100 parts of gradient polyether alcohol intermediate, the amount of Raney nickel catalyst is 10-14 parts, the amount of anhydrous liquid ammonia is 50-70 parts, the hydrogen pressure is 5-7 MPa, the catalytic amination temperature is 210-230℃, and the catalytic amination time is 6-10 h; the hydroxyl value of the main clean molecule of the gradient polyether amine obtained by catalytic amination is 2.5-4 mg KOH / g.

[0016] Preferably, the fuel detergent composition comprises, by weight, 100 parts of graded polyetheramine main detergent molecules, 80 parts of aromatic solvent oil and 2 parts of 2,6-di-tert-butyl-p-cresol.

[0017] Furthermore, the present invention also provides a method for preparing a fuel detergent composition, comprising the following steps:

[0018] (1) Highly reactive polyisobutylene is subjected to hydroboration and oxidation reactions to obtain monohydroxy polyisobutylene intermediate;

[0019] (2) After the monohydroxy polyisobutylene intermediate is converted into polyisobutylene alkoxide starting seed, propylene oxide is added first to react. After the residual propylene oxide is less than 2 g / kg, the first part of ethylene oxide and the second part of ethylene oxide are added in sequence to react and obtain gradient polyether alcohol intermediate.

[0020] (3) The gradient polyether alcohol intermediate is subjected to catalytic amination with anhydrous liquid ammonia and hydrogen in the presence of Raney nickel catalyst to obtain the gradient polyether amine main clean molecule;

[0021] (4) The gradient polyetheramine main cleaning molecule, aromatic solvent oil and 2,6-di-tert-butyl-p-cresol are mixed and filtered to obtain a fuel cleaning agent composition.

[0022] Preferably, in step (4), mixing and filtering is performed by stirring at 300 r / min for 1 h at 50 °C and then filtering through a 5 μm filter.

[0023] The beneficial effects of this invention are:

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] (1) The present invention provides unilateral oleophobic end groups through highly reactive polyisobutylene, provides fuel compatibility and high-temperature surface retention capacity through polyoxypropylene segments, and forms adjacent polar anchoring regions with terminal primary amines through polyoxyethylene enrichment segments at the end of the chain, so that the resulting gradient polyetheramine main cleaning molecules have oil solubility, deposit affinity and polar adsorption capacity.

[0026] (2) In this invention, ethylene oxide is added sequentially in two batches after the residual amount of propylene oxide is less than 2 g / kg, so that the polyoxyethylene structural units at the end of the chain form a controllable enrichment near the terminal amino groups. Compared with the control system in which alkyl propylene oxide is added in mixture or all ethylene oxide is added at once, the detergent obtained by this invention shows better overall performance in simulating intake valve deposits, injector flow recovery, spray cone angle maintenance, and flow retention after hot soaking.

[0027] (3) The fuel detergent composition obtained by the present invention can be dispersed in automotive gasoline at a low addition amount, maintain good transparency under low temperature conditions, reduce intake valve deposits and electronic orifice nozzle clogging tendency, and improve flow recovery and atomization uniformity after in-cylinder direct injection fuel injector contamination. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0029] All examples and comparative examples were prepared and tested using the same batch of raw materials and the same batch of base fuel. The highly reactive polyisobutylene used was BASF's GLISSOPAL 1000, with a number-average molecular weight of 1000 and a terminal vinylidene double bond molar content of 87.4%; the borane dimethyl sulfide complex solution was a 2 mol / L tetrahydrofuran solution (Shanghai Aladdin Biochemical Technology Co., Ltd., catalog number B130054); propylene oxide was Shanghai Aladdin Biochemical Technology Co., Ltd., catalog number P109311, with a mass fraction of not less than 995 g / kg; ethylene oxide was Shanghai Aladdin Biochemical Technology Co., Ltd., catalog number E105779, with a mass fraction of not less than 995 g / kg; and the Raney nickel catalyst was Shanghai Aladdin Biochemical Technology Co., Ltd., catalog number R111434, with a particle size... The particles are no larger than 150 μm and dispersed in water; 18-crown ether-6 is product number C124569 from Shanghai Aladdin Biochemical Technology Co., Ltd., with a purity of not less than 99%; potassium tert-butoxide is product number P111076 from Shanghai Aladdin Biochemical Technology Co., Ltd., with a purity of not less than 98%; the aromatic solvent oil is Shell Sol A150, a high-boiling-point aromatic solvent oil from Shell Chemicals; anhydrous liquid ammonia is anhydrous ammonia in cylinders from Linde Gases China Ltd., with a purity of not less than 99%; hydrogen and nitrogen are gases in cylinders from Linde Gases China Ltd., with a purity of not less than 99%; and hydrogen peroxide solution is a commercially available analytical grade reagent with a mass fraction of 30%.

[0030] Example 1:

[0031] Step 1: Add 400g of anhydrous n-hexane and 200g of highly reactive polyisobutylene to a dry four-necked reaction flask. Stir at 300r / min for 30min under nitrogen protection, then cool the reaction system to 0-5℃. Add 120g of borane dimethyl sulfide complex solution dropwise over 40min, maintaining the reaction system temperature at 0-5℃ during the dropwise addition. After the dropwise addition is complete, continue the reaction at 0-5℃ for 2h, then raise the temperature to 40℃ and react for 3h. After the reaction is complete, cool the system to 5-10℃, and add an aqueous sodium hydroxide solution prepared from 15g of sodium hydroxide and 135g of deionized water over 30min. Continue stirring for 20min. Then add 100g of hydrogen peroxide solution in three portions, with each addition being 34g, 33g, and 33g, 15min apart. Maintain the reaction system temperature at 5-15℃ during the addition. After the addition is complete, react at 25℃ for 2h. After the reaction solution was allowed to stand for 30 min, the organic layer was separated and washed once with deionized water and once with saturated sodium chloride aqueous solution. The organic layer was then dehydrated at 60 °C and 10 kPa to remove n-hexane and tetrahydrofuran, and then dehydrated at 100 °C and 800 Pa for 1 h to obtain monohydroxy polyisobutylene intermediate.

[0032] Step 2: Add 150g of monohydroxy polyisobutylene intermediate to a dry, pressure-resistant reactor and dehydrate it at 110℃ and 500Pa for 1 hour until the moisture content is below 300mg / kg. After cooling to 25℃, add 40g of anhydrous toluene, 20g of anhydrous tetrahydrofuran, 5g of 18-crown ether-6, and 2g of potassium tert-butoxide to the reactor. Stir at 400r / min for 30min under nitrogen protection to generate polyisobutylene alkoxide starting seed. Cool the reactor to 15℃ and add 40g of propylene oxide over 2 hours, keeping the temperature inside the reactor between 15-20℃ during the addition. After the addition is complete, react at 25℃ for 4 hours, then raise the temperature to 35℃ and continue reacting until the residual propylene oxide content is below 2g / kg as detected by gas chromatography. Subsequently, without separating the reaction solution, the reaction vessel was cooled to 0-5℃, and 4g of the first ethylene oxide was added within 30 minutes. After maintaining the temperature at 0-5℃ for 1 hour, the temperature was raised to 20℃ and reacted for 2 hours until the residual ethylene oxide was less than 2g / kg as detected by gas chromatography. Then, the reaction vessel was cooled to 0-5℃ again, and 8g of the second ethylene oxide was added within 40 minutes. After the addition was completed, the temperature was maintained at 0-5℃ for 1 hour, and then raised to 30-35℃ and reacted for 4 hours until the residual ethylene oxide was less than 2g / kg as detected by gas chromatography. After the reaction was completed, 2g of glacial acetic acid was added to neutralize for 15 minutes, and the inorganic salts were removed by filtration. The filtrate was subjected to solvent removal and removal of unreacted small molecules at 80℃ and 5kPa to obtain a gradient polyether alcohol intermediate. The number average molecular weight of the gradient polyether alcohol intermediate was determined to be 1500 by gel permeation chromatography, and the hydroxyl value was determined to be 40mg KOH / g by the hydroxyl value method.

[0033] Step 3: Add 12g of Raney nickel catalyst to 50g of anhydrous isopropanol, stir for 5 minutes, filter, and then replace once with 50g of anhydrous isopropanol, followed by once with 30g of anhydrous toluene; keep the Raney nickel catalyst covered by liquid during the replacement process, without drying; add 100g of gradient polyether alcohol intermediate and the replaced Raney nickel catalyst to a 2L autoclave, replace the autoclave three times with nitrogen, cool to -10℃, and add 60g of anhydrous liquid ammonia; seal the autoclave, heat to 25℃, and then purge with hydrogen to 6MPa. a) The temperature was then raised to 220℃ and reacted for 8 hours. During the reaction, the stirring speed was maintained at 600 r / min, and the maximum pressure inside the reactor was controlled below 18 MPa. After the reaction, the high-pressure reactor was cooled to below 40℃ and depressurized to atmospheric pressure. The Raney nickel catalyst was removed by filtration. The filtrate was first deammonened at 60℃, and then demineralized at 110℃ and 500 Pa for 1 hour to remove low-boiling substances, thus obtaining the gradient polyetheramine main cleaning molecule. The total amine value of the gradient polyetheramine main cleaning molecule was determined to be 37.2 mg KOH / g by the total amine value method, and the hydroxyl value was determined to be 3 mg KOH / g by the hydroxyl value method.

[0034] Step 4: Add 100g of gradient polyetheramine main cleaning molecule, 80g of aromatic solvent oil and 2g of 2,6-di-tert-butyl-p-cresol to the mixing container, stir at 300r / min for 1h at 50℃, and filter through a 5μm filter element to obtain the fuel cleaning agent composition.

[0035] Example 2:

[0036] Step 1: Add 360g of anhydrous n-hexane and 180g of highly reactive polyisobutylene to a dry four-necked reaction flask. Stir at 300r / min for 30min under nitrogen protection, then cool the reaction system to 0-5℃. Add 108g of borane dimethyl sulfide complex solution dropwise over 40min, maintaining the reaction system temperature at 0-5℃ during the dropwise addition. After the dropwise addition is complete, continue the reaction at 0-5℃ for 2h, then raise the temperature to 40℃ and react for 3h. After the reaction is complete, cool the system to 5-10℃, and add an aqueous sodium hydroxide solution prepared from 14g of sodium hydroxide and 126g of deionized water over 30min. Continue stirring for 20min. Then add 90g of hydrogen peroxide solution in three portions, each 30g, with 15min intervals between each addition. Maintain the reaction system temperature at 5-15℃ during the addition. After the addition is complete, react at 25℃ for 2h. After the reaction solution was allowed to stand for 30 min, the organic layer was separated and washed once with deionized water and once with saturated sodium chloride aqueous solution. The organic layer was then dehydrated at 60 °C and 10 kPa to remove n-hexane and tetrahydrofuran, and then dehydrated at 100 °C and 800 Pa for 1 h to obtain monohydroxy polyisobutylene intermediate.

[0037] Step 2: Add 140g of monohydroxy polyisobutylene intermediate to a dry, pressure-resistant reactor and dehydrate it at 110℃ and 500Pa for 1 hour until the moisture content is below 300mg / kg. After cooling to 25℃, add 35g of anhydrous toluene, 15g of anhydrous tetrahydrofuran, 4g of 18-crown ether-6, and 1.5g of potassium tert-butoxide to the reactor. Stir at 400r / min for 30 minutes under nitrogen protection to generate polyisobutylene alkoxide starting seed. Cool the reactor to 15℃ and add 32g of propylene oxide over 2 hours, keeping the temperature inside the reactor between 15-20℃ during the addition. After the addition is complete, react at 25℃ for 4 hours, then raise the temperature to 35℃ and continue reacting until the residual propylene oxide content is below 2g / kg as detected by gas chromatography. Subsequently, without separating the reaction solution, the reaction vessel was cooled to 0-5℃, and 3g of the first ethylene oxide was added within 30 minutes. After maintaining the temperature at 0-5℃ for 1 hour, the temperature was raised to 20℃ and reacted for 2 hours until the residual ethylene oxide was less than 2g / kg as detected by gas chromatography. Then, the reaction vessel was cooled to 0-5℃ again, and 6g of the second ethylene oxide was added within 40 minutes. After the addition was completed, the temperature was maintained at 0-5℃ for 1 hour, and then raised to 30-35℃ and reacted for 4 hours until the residual ethylene oxide was less than 2g / kg as detected by gas chromatography. After the reaction was completed, 1.5g of glacial acetic acid was added to neutralize for 15 minutes, and the inorganic salts were removed by filtration. The filtrate was subjected to solvent removal and removal of unreacted small molecules at 80℃ and 5kPa to obtain a gradient polyether alcohol intermediate. The number average molecular weight of the gradient polyether alcohol intermediate was determined to be 1300 by gel permeation chromatography, and the hydroxyl value was determined to be 43mg KOH / g by the hydroxyl value method.

[0038] Step 3: Add 10g of Raney nickel catalyst to 40g of anhydrous isopropanol, stir for 5 minutes, filter, and then replace once with 40g of anhydrous isopropanol, followed by once with 25g of anhydrous toluene; keep the Raney nickel catalyst covered by liquid during the replacement process, without drying; add 100g of gradient polyether alcohol intermediate and the replaced Raney nickel catalyst to a 2L autoclave, replace the autoclave three times with nitrogen, cool to -10℃, and add 50g of anhydrous liquid ammonia; seal the autoclave, heat to 25℃, and then purge with hydrogen to 5MPa. a. The temperature was then raised to 210℃ and reacted for 6 hours. During the reaction, the stirring speed was maintained at 600 r / min, and the maximum pressure inside the reactor was controlled below 18 MPa. After the reaction, the high-pressure reactor was cooled to below 40℃ and depressurized to atmospheric pressure. The Raney nickel catalyst was removed by filtration. The filtrate was first deammonened at 60℃, and then demineralized at 110℃ and 500 Pa for 1 hour to remove low-boiling substances, thus obtaining the gradient polyetheramine main cleaning molecule. The total amine value of the gradient polyetheramine main cleaning molecule was determined to be 42.9 mg KOH / g by the total amine value method, and the hydroxyl value was determined to be 4 mg KOH / g by the hydroxyl value method.

[0039] Step 4: Add 90g of gradient polyetheramine main cleaning molecules, 70g of aromatic solvent oil and 1g of 2,6-di-tert-butyl-p-cresol to the mixing container, stir at 300r / min for 1h at 50℃, and filter through a 5μm filter element to obtain the fuel cleaning agent composition.

[0040] Example 3:

[0041] Step 1: Add 390g of anhydrous n-hexane and 195g of highly reactive polyisobutylene to a dry four-necked reaction flask. Stir at 300r / min for 30min under nitrogen protection, then cool the reaction system to 0-5℃. Add 115g of borane dimethyl sulfide complex solution dropwise over 40min, maintaining the reaction system temperature at 0-5℃ during the dropwise addition. After the dropwise addition is complete, continue the reaction at 0-5℃ for 2h, then raise the temperature to 40℃ and react for 3h. After the reaction is complete, cool the system to 5-10℃, and add an aqueous sodium hydroxide solution prepared from 15g of sodium hydroxide and 135g of deionized water over 30min. Continue stirring for 20min. Then add 96g of hydrogen peroxide solution in three portions, each 32g, with 15min intervals between each addition. Maintain the reaction system temperature at 5-15℃ during the addition. After the addition is complete, react at 25℃ for 2h. After the reaction solution was allowed to stand for 30 min, the organic layer was separated and washed once with deionized water and once with saturated sodium chloride aqueous solution. The organic layer was then dehydrated at 60 °C and 10 kPa to remove n-hexane and tetrahydrofuran, and then dehydrated at 100 °C and 800 Pa for 1 h to obtain monohydroxy polyisobutylene intermediate.

[0042] Step 2: Add 145g of monohydroxy polyisobutylene intermediate to a dry, pressure-resistant reactor and dehydrate it at 110℃ and 500Pa for 1 hour until the moisture content is below 300mg / kg. After cooling to 25℃, add 38g of anhydrous toluene, 18g of anhydrous tetrahydrofuran, 4.5g of 18-crown ether-6, and 1.8g of potassium tert-butoxide to the reactor. Stir at 400r / min for 30 minutes under nitrogen protection to generate polyisobutylene alkoxide starting seed. Cool the reactor to 15℃ and add 36g of propylene oxide over 2 hours, controlling the temperature inside the reactor at 15-20℃ during the addition process. After the addition is complete, react at 25℃ for 4 hours, then raise the temperature to 35℃ and continue reacting until the residual propylene oxide content is below 2g / kg as detected by gas chromatography. Subsequently, without separating the reaction solution, the reaction vessel was cooled to 0-5℃, and 5g of the first ethylene oxide was added within 30 minutes. After maintaining the temperature at 0-5℃ for 1 hour, the temperature was raised to 20℃ and reacted for 2 hours until the residual ethylene oxide was less than 2g / kg as detected by gas chromatography. Then, the reaction vessel was cooled to 0-5℃ again, and 6g of the second ethylene oxide was added within 40 minutes. After the addition was completed, the temperature was maintained at 0-5℃ for 1 hour, and then raised to 30-35℃ and reacted for 4 hours until the residual ethylene oxide was less than 2g / kg as detected by gas chromatography. After the reaction was completed, 1.8g of glacial acetic acid was added to neutralize for 15 minutes, and the inorganic salts were removed by filtration. The filtrate was subjected to solvent removal and removal of unreacted small molecules at 80℃ and 5kPa to obtain a gradient polyether alcohol intermediate. The number average molecular weight of the gradient polyether alcohol intermediate was determined to be 1400 by gel permeation chromatography, and the hydroxyl value was determined to be 42mg KOH / g by the hydroxyl value method.

[0043] Step 3: Add 11g of Raney nickel catalyst to 45g of anhydrous isopropanol, stir for 5 minutes, filter, and then replace once with 45g of anhydrous isopropanol, followed by once with 28g of anhydrous toluene; keep the Raney nickel catalyst covered by liquid during the replacement process, without drying; add 100g of gradient polyether alcohol intermediate and the replaced Raney nickel catalyst to a 2L autoclave, replace the autoclave three times with nitrogen, cool to -10℃, and add 55g of anhydrous liquid ammonia; seal the autoclave and heat to 25℃. Hydrogen gas was then introduced to 5.5 MPa, and the temperature was raised to 215 °C for 7 hours. During the reaction, the stirring speed was maintained at 600 r / min, and the maximum pressure inside the reactor was controlled below 18 MPa. After the reaction, the high-pressure reactor was cooled to below 40 °C, depressurized to atmospheric pressure, and the Raney nickel catalyst was removed by filtration. The filtrate was first deammoniated at 60 °C, and then low-boiling substances were removed at 110 °C and 500 Pa for 1 hour to obtain the gradient polyetheramine main cleaning molecule. The total amine value of the gradient polyetheramine main cleaning molecule was determined to be 39.5 mg KOH / g by the total amine value method, and the hydroxyl value was determined to be 3.5 mg KOH / g by the hydroxyl value method.

[0044] Step 4: Add 100g of gradient polyetheramine main cleaning molecule, 75g of aromatic solvent oil and 1.5g of 2,6-di-tert-butyl-p-cresol to the mixing container, stir at 300r / min for 1h at 50℃, and filter through a 5μm filter element to obtain the fuel cleaning agent composition.

[0045] Example 4:

[0046] Step 1: Add 420g of anhydrous n-hexane and 210g of highly reactive polyisobutylene to a dry four-necked reaction flask. Stir at 300r / min for 30min under nitrogen protection, then cool the reaction system to 0-5℃. Add 126g of borane dimethyl sulfide complex solution dropwise over 40min, maintaining the reaction system temperature at 0-5℃ during the dropwise addition. After the dropwise addition is complete, continue the reaction at 0-5℃ for 2h, then raise the temperature to 40℃ and react for 3h. After the reaction is complete, cool the system to 5-10℃, and add an aqueous sodium hydroxide solution prepared from 16g of sodium hydroxide and 144g of deionized water over 30min. Continue stirring for 20min. Then add 105g of hydrogen peroxide solution in three portions, each 35g, with 15min intervals between each addition. Maintain the reaction system temperature at 5-15℃ during the addition. After the addition is complete, react at 25℃ for 2h. After the reaction solution was allowed to stand for 30 min, the organic layer was separated and washed once with deionized water and once with saturated sodium chloride aqueous solution. The organic layer was then dehydrated at 60 °C and 10 kPa to remove n-hexane and tetrahydrofuran, and then dehydrated at 100 °C and 800 Pa for 1 h to obtain monohydroxy polyisobutylene intermediate.

[0047] Step 2: Add 155g of monohydroxy polyisobutylene intermediate to a dry, pressure-resistant reactor and dehydrate it at 110℃ and 500Pa for 1 hour until the moisture content is below 300mg / kg. After cooling to 25℃, add 43g of anhydrous toluene, 22g of anhydrous tetrahydrofuran, 5.5g of 18-crown ether-6, and 2.2g of potassium tert-butoxide to the reactor. Stir at 400r / min for 30 minutes under nitrogen protection to generate polyisobutylene alkoxide starting seed. Cool the reactor to 15℃ and add 44g of propylene oxide over 2 hours, keeping the temperature inside the reactor between 15-20℃ during the addition. After the addition is complete, react at 25℃ for 4 hours, then raise the temperature to 35℃ and continue reacting until the residual propylene oxide content is below 2g / kg as detected by gas chromatography. Subsequently, without separating the reaction solution, the reaction vessel was cooled to 0-5℃, and 4g of the first ethylene oxide was added within 30 minutes. After maintaining the temperature at 0-5℃ for 1 hour, the temperature was raised to 20℃ and reacted for 2 hours until the residual ethylene oxide was less than 2g / kg as detected by gas chromatography. Then, the reaction vessel was cooled to 0-5℃ again, and 9g of the second ethylene oxide was added within 40 minutes. After the addition was completed, the temperature was maintained at 0-5℃ for 1 hour, and then raised to 30-35℃ and reacted for 4 hours until the residual ethylene oxide was less than 2g / kg as detected by gas chromatography. After the reaction was completed, 2.2g of glacial acetic acid was added to neutralize for 15 minutes, and the inorganic salts were removed by filtration. The filtrate was subjected to solvent removal and removal of unreacted small molecules at 80℃ and 5kPa to obtain a gradient polyether alcohol intermediate. The number average molecular weight of the gradient polyether alcohol intermediate was determined to be 1550 by gel permeation chromatography, and the hydroxyl value was determined to be 38mg KOH / g by the hydroxyl value method.

[0048] Step 3: Add 13g of Raney nickel catalyst to 55g of anhydrous isopropanol, stir for 5 minutes, filter, and then replace once with 55g of anhydrous isopropanol, followed by once with 32g of anhydrous toluene; keep the Raney nickel catalyst covered by liquid during the replacement process, without drying; add 100g of gradient polyether alcohol intermediate and the replaced Raney nickel catalyst to a 2L autoclave, replace the autoclave three times with nitrogen, cool to -10℃, and add 65g of anhydrous liquid ammonia; seal the autoclave and heat to 25℃. Hydrogen gas was then introduced to 6.5 MPa, and the temperature was raised to 225 °C for 9 hours. During the reaction, the stirring speed was maintained at 600 r / min, and the maximum pressure inside the reactor was controlled below 18 MPa. After the reaction, the high-pressure reactor was cooled to below 40 °C, depressurized to atmospheric pressure, and the Raney nickel catalyst was removed by filtration. The filtrate was first deammonened at 60 °C, and then demineralized at 110 °C and 500 Pa for 1 hour to remove low-boiling substances, yielding the gradient polyetheramine main cleaning molecule. The total amine value of the gradient polyetheramine main cleaning molecule was determined to be 36.2 mg KOH / g by the total amine value method, and the hydroxyl value was determined to be 3 mg KOH / g by the hydroxyl value method.

[0049] Step 4: Add 105g of gradient polyetheramine main cleaning molecule, 85g of aromatic solvent oil and 2.5g of 2,6-di-tert-butyl-p-cresol to the mixing container, stir at 300r / min for 1h at 50℃, and filter through a 5μm filter element to obtain the fuel cleaning agent composition.

[0050] Example 5:

[0051] Step 1: Add 440g of anhydrous n-hexane and 220g of highly reactive polyisobutylene to a dry four-necked reaction flask. Stir at 300r / min for 30min under nitrogen protection, then cool the reaction system to 0-5℃. Add 132g of borane dimethyl sulfide complex solution dropwise over 40min, maintaining the reaction system temperature at 0-5℃ during the dropwise addition. After the dropwise addition is complete, continue the reaction at 0-5℃ for 2h, then raise the temperature to 40℃ and react for 3h. After the reaction is complete, cool the system to 5-10℃, and add an aqueous sodium hydroxide solution prepared from 18g of sodium hydroxide and 150g of deionized water over 30min, continuing to stir for 20min. Then add 110g of hydrogen peroxide solution in three portions, with each addition being 37g, 37g, and 36g, 15min apart, maintaining the reaction system temperature at 5-15℃ during the addition. After the addition is complete, react at 25℃ for 2h. After the reaction solution was allowed to stand for 30 min, the organic layer was separated and washed once with deionized water and once with saturated sodium chloride aqueous solution. The organic layer was then dehydrated at 60 °C and 10 kPa to remove n-hexane and tetrahydrofuran, and then dehydrated at 100 °C and 800 Pa for 1 h to obtain monohydroxy polyisobutylene intermediate.

[0052] Step 2: Add 160g of monohydroxy polyisobutylene intermediate to a dry, pressure-resistant reactor and dehydrate it at 110℃ and 500Pa for 1 hour until the moisture content is below 300mg / kg. After cooling to 25℃, add 45g of anhydrous toluene, 25g of anhydrous tetrahydrofuran, 6g of 18-crown ether-6, and 2.5g of potassium tert-butoxide to the reactor. Stir at 400r / min for 30 minutes under nitrogen protection to generate polyisobutylene alkoxide starting seed. Cool the reactor to 15℃ and add 48g of propylene oxide over 2 hours, keeping the temperature inside the reactor between 15-20℃ during the addition. After the addition is complete, react at 25℃ for 4 hours, then raise the temperature to 35℃ and continue reacting until the residual propylene oxide content is below 2g / kg as detected by gas chromatography. Subsequently, without separating the reaction solution, the reaction vessel was cooled to 0-5℃, and 5g of the first ethylene oxide was added within 30 minutes. After maintaining the temperature at 0-5℃ for 1 hour, the temperature was raised to 20℃ and reacted for 2 hours until the residual ethylene oxide was less than 2g / kg as detected by gas chromatography. Then, the reaction vessel was cooled to 0-5℃ again, and 10g of the second ethylene oxide was added within 40 minutes. After the addition was completed, the temperature was maintained at 0-5℃ for 1 hour, and then raised to 30-35℃ and reacted for 4 hours until the residual ethylene oxide was less than 2g / kg as detected by gas chromatography. After the reaction was completed, 2.5g of glacial acetic acid was added to neutralize for 15 minutes, and inorganic salts were removed by filtration. The filtrate was subjected to solvent removal and removal of unreacted small molecules at 80℃ and 5kPa to obtain a gradient polyether alcohol intermediate. The number average molecular weight of the gradient polyether alcohol intermediate was determined to be 1600 by gel permeation chromatography, and the hydroxyl value was determined to be 36mg KOH / g by the hydroxyl value method.

[0053] Step 3: Add 14g of Raney nickel catalyst to 60g of anhydrous isopropanol, stir for 5 minutes, filter, and then repeat the displacement once with 60g of anhydrous isopropanol, followed by displacement once with 35g of anhydrous toluene; during the displacement process, keep the Raney nickel catalyst covered by liquid and do not dry it; add 100g of gradient polyether alcohol intermediate and the displacement Raney nickel catalyst to a 2L autoclave, purge the autoclave three times with nitrogen, cool to -10℃, and add 70g of anhydrous liquid ammonia; seal the autoclave and heat to 25℃. After reaching 7 MPa, hydrogen gas was introduced and the temperature was raised to 230℃ for 10 hours. During the reaction, the stirring speed was maintained at 600 r / min, and the maximum pressure inside the reactor was controlled below 18 MPa. After the reaction, the pressure vessel was cooled to below 40℃ and depressurized to atmospheric pressure. The Raney nickel catalyst was removed by filtration. The filtrate was first deammonerated at 60℃, and then low-boiling substances were removed at 110℃ and 500 Pa for 1 hour to obtain the gradient polyetheramine main cleaning molecule. The total amine value of the gradient polyetheramine main cleaning molecule was determined to be 35.0 mg KOH / g by the total amine value method, and the hydroxyl value was determined to be 2.5 mg KOH / g by the hydroxyl value method.

[0054] Step 4: Add 110g of gradient polyetheramine main cleaning molecule, 90g of aromatic solvent oil and 3g of 2,6-di-tert-butyl-p-cresol to the mixing container, stir at 300r / min for 1h at 50℃, and filter through a 5μm filter element to obtain the fuel cleaning agent composition.

[0055] Example 6:

[0056] Step 1: Add 380g of anhydrous n-hexane and 190g of highly reactive polyisobutylene to a dry four-necked reaction flask. Stir at 300r / min for 30min under nitrogen protection, then cool the reaction system to 0-5℃. Add 114g of borane dimethyl sulfide complex solution dropwise over 40min, maintaining the reaction system temperature at 0-5℃ during the dropwise addition. After the dropwise addition is complete, continue the reaction at 0-5℃ for 2h, then raise the temperature to 40℃ and react for 3h. After the reaction is complete, cool the system to 5-10℃, and add an aqueous sodium hydroxide solution prepared from 15g of sodium hydroxide and 135g of deionized water over 30min. Continue stirring for 20min. Then add 95g of hydrogen peroxide solution in three portions, with each addition being 32g, 32g, and 31g, 15min apart. Maintain the reaction system temperature at 5-15℃ during the addition. After the addition is complete, react at 25℃ for 2h. After the reaction solution was allowed to stand for 30 min, the organic layer was separated and washed once with deionized water and once with saturated sodium chloride aqueous solution. The organic layer was then dehydrated at 60 °C and 10 kPa to remove n-hexane and tetrahydrofuran, and then dehydrated at 100 °C and 800 Pa for 1 h to obtain monohydroxy polyisobutylene intermediate.

[0057] Step 2: Add 150g of monohydroxy polyisobutylene intermediate to a dry, pressure-resistant reactor and dehydrate it at 110℃ and 500Pa for 1 hour until the moisture content is below 300mg / kg. After cooling to 25℃, add 40g of anhydrous toluene, 20g of anhydrous tetrahydrofuran, 5g of 18-crown ether-6, and 2g of potassium tert-butoxide to the reactor. Stir at 400r / min for 30 minutes under nitrogen protection to generate polyisobutylene alkoxide starting seeds. Cool the reactor to 15℃ and add 42g of propylene oxide over 2 hours, keeping the temperature inside the reactor between 15-20℃ during the addition process. After the addition is complete, react at 25℃ for 4 hours, then raise the temperature to 35℃ and continue reacting until the residual propylene oxide content is below 2g / kg as detected by gas chromatography. Subsequently, without separating the reaction solution, the reaction vessel was cooled to 0-5℃, and 3g of the first ethylene oxide was added within 30 minutes. After maintaining the temperature at 0-5℃ for 1 hour, the temperature was raised to 20℃ and reacted for 2 hours until the residual ethylene oxide was less than 2g / kg as detected by gas chromatography. Then, the reaction vessel was cooled to 0-5℃ again, and 9g of the second ethylene oxide was added within 40 minutes. After the addition was completed, the temperature was maintained at 0-5℃ for 1 hour, and then raised to 30-35℃ and reacted for 4 hours until the residual ethylene oxide was less than 2g / kg as detected by gas chromatography. After the reaction was completed, 2g of glacial acetic acid was added to neutralize for 15 minutes, and the inorganic salts were removed by filtration. The filtrate was subjected to solvent removal and removal of unreacted small molecules at 80℃ and 5kPa to obtain a gradient polyether alcohol intermediate. The number average molecular weight of the gradient polyether alcohol intermediate was determined to be 1480 by gel permeation chromatography, and the hydroxyl value was determined to be 40mg KOH / g by the hydroxyl value method.

[0058] Step 3: Add 12g of Raney nickel catalyst to 50g of anhydrous isopropanol, stir for 5 minutes, filter, and then replace once with 50g of anhydrous isopropanol, followed by once with 30g of anhydrous toluene; keep the Raney nickel catalyst covered by liquid during the replacement process, without drying; add 100g of gradient polyether alcohol intermediate and the replaced Raney nickel catalyst to a 2L autoclave, replace the autoclave three times with nitrogen, cool to -10℃, and add 60g of anhydrous liquid ammonia; seal the autoclave, heat to 25℃, and then purge with hydrogen to 6MPa. a. The temperature was then raised to 215℃ and reacted for 8 hours. During the reaction, the stirring speed was maintained at 600 r / min, and the maximum pressure inside the reactor was controlled below 18 MPa. After the reaction, the high-pressure reactor was cooled to below 40℃, depressurized to atmospheric pressure, and the Raney nickel catalyst was removed by filtration. The filtrate was first deammonened at 60℃, and then demineralized at 110℃ and 500 Pa for 1 hour to remove low-boiling substances, yielding the gradient polyetheramine main cleaning molecule. The total amine value of the gradient polyetheramine main cleaning molecule was determined to be 43 mg KOH / g by the total amine value method, and the hydroxyl value was determined to be 3.5 mg KOH / g by the hydroxyl value method.

[0059] Step 4: Add 100g of gradient polyetheramine main cleaning molecule, 80g of aromatic solvent oil and 2g of 2,6-di-tert-butyl-p-cresol to the mixing container, stir at 300r / min for 1h at 50℃, and filter through a 5μm filter element to obtain the fuel cleaning agent composition.

[0060] Comparative Example 1:

[0061] The difference from Example 1 is as follows: in step two, 150g of monohydroxy polyisobutylene intermediate is not added, and the amount of anhydrous toluene added is adjusted from 40g to 190g. The reaction of propylene oxide, the first part of ethylene oxide and the second part of ethylene oxide are carried out in the same presence of anhydrous tetrahydrofuran, 18-crown ether-6 and potassium tert-butoxide. In step three, the intermediate obtained in step two is used instead of the gradient polyether alcohol intermediate in Example 1 for catalytic amination. In step four, 100g of the product obtained in step three is used instead of 100g of the gradient polyether amine main cleaning molecule in Example 1. The other conditions are the same as in Example 1.

[0062] Comparative Example 2:

[0063] The difference from Example 1 is that in step two, after generating the polyisobutylene alkoxide starting seed, 4g of the first part of ethylene oxide is added and reacted at the same temperature and time as in Example 1, then 8g of the second part of ethylene oxide is added and reacted at the same temperature and time as in Example 1, and finally 40g of propylene oxide is added and reacted at the same temperature and time as in Example 1; the remaining conditions are the same as in Example 1.

[0064] Comparative Example 3:

[0065] The difference from Example 1 is that in step two, 40g of propylene oxide, 4g of the first part of ethylene oxide and 8g of the second part of ethylene oxide are premixed into a mixed epoxide and added to the reactor within 2 hours. Instead of adding the first part of ethylene oxide and the second part of ethylene oxide sequentially after the propylene oxide conversion is completed, the total amount of epoxide added is the same as in Example 1, and the other conditions are the same as in Example 1.

[0066] Comparative Example 4:

[0067] The difference from Example 1 is that in step two, after the propylene oxide reaction is completed and the residual propylene oxide is confirmed to be less than 2 g / kg, 4 g of the first ethylene oxide and 8 g of the second ethylene oxide are combined into 12 g of ethylene oxide, which is added to the reactor in one go within 70 min. After the addition is completed, the temperature is maintained at 0-5℃ for 1 h, and then the temperature is raised to 30-35℃ for 4 h until the residual ethylene oxide is detected by gas chromatography to be less than 2 g / kg; the other conditions are the same as in Example 1.

[0068] Comparative Example 5:

[0069] The difference from Example 1 is that the liquid ammonia and hydrogen catalytic amination in step three is not performed, and in step four, 100g of the gradient polyether alcohol intermediate obtained in step two of Example 1 is used to replace 100g of the gradient polyether amine main cleaning molecule; the other conditions are the same as in Example 1.

[0070] The difference between Comparative Example 6 and Example 1 is that the amount of propylene oxide added in step two was adjusted from 40g to 28g, the amount of the first batch of ethylene oxide added was adjusted from 4g to 3g, and the amount of the second batch of ethylene oxide added was adjusted from 8g to 6g, so that the number average molecular weight of the resulting gradient polyether alcohol intermediate was 1200; the other conditions were the same as in Example 1.

[0071] Comparative Example 7:

[0072] The difference from Example 1 is that in step two, the amount of propylene oxide added is adjusted from 40g to 56g, the amount of the first batch of ethylene oxide added is adjusted from 4g to 6g, and the amount of the second batch of ethylene oxide added is adjusted from 8g to 12g, so that the number average molecular weight of the resulting gradient polyether alcohol intermediate is 1750; the other conditions are the same as in Example 1.

[0073] Total amine value was determined by non-aqueous potentiometric titration: approximately 0.5 g of sample was weighed, dissolved in a mixed solvent of isopropanol / toluene, and titrated with a standard hydrochloric acid-isopropanol solution. The result was corrected with a blank test and expressed as mg KOH / g. Primary amine value was determined by non-aqueous titration after salicylaldehyde derivatization. Hydroxyl value was determined by acetylation-back titration method, and the result is expressed as mg KOH / g.

[0074] Residual propylene oxide and residual ethylene oxide were determined by gas chromatography with an FID detector and external standard method for quantification. The method detection limit was not higher than 0.2 g / kg, and the quantification limit was not higher than 0.5 g / kg. When the residual propylene oxide or residual ethylene oxide value was lower than 2 g / kg, the corresponding reaction stage was deemed to have met the conditions for the next feeding step.

[0075] Sample preparation for performance testing: The fuel detergent compositions obtained in Examples 1-6 and Comparative Examples 1-7 were used as test samples and labeled as E1, E2, E3, E4, E5, E6, D1, D2, D3, D4, D5, D6, and D7, respectively. Base gasoline without the added fuel detergent composition was used as a blank sample and labeled B0. The base gasoline used was 95-octane gasoline conforming to GB 17930-2016. Before the performance test, 0.800g of each test sample was weighed and added to 999.200g of base gasoline. The mixture was magnetically stirred at 600r / min for 30min at 25℃ and allowed to stand for 2h to obtain the additive-added gasoline. All samples were sealed and placed at 25℃ in the dark for 24h before testing.

[0076] The test results are shown in Table 1.

[0077] Moisture content and low-temperature gasoline compatibility test: Moisture content was determined according to GB / T 11133-2015. 1.000g of the fuel detergent composition was weighed, and the water content was determined by Karl Fischer coulometric titration. The result is expressed in mg / kg. For the low-temperature gasoline compatibility test, each fuel detergent composition was added at 800mg / kg to 95-octane gasoline conforming to GB 17930-2016 to obtain additive gasoline. 100mL of additive gasoline was placed in a transparent glass bottle with a PTFE gasket and placed in a -20℃ constant temperature chamber for 72h. The transmittance was then measured at -20℃ and a wavelength of 600nm. Three bottles were tested for each sample, and the lowest transmittance was recorded as the result.

[0078] Simulated intake valve deposit test: The detergency of additive gasoline was evaluated according to the apparatus and weighing rules of GB / T 37322-2019. The deposit collector was cleaned, dried, and weighed to 0.1 mg, then installed in the simulated intake valve deposit test apparatus. The surface temperature of the deposit collector was set to 175℃, the air flow rate to 80 mL / min, and the fuel supply rate to 0.30 mL / min. The test duration was 90 min. After the test, the deposit collector was cooled in a desiccator for 30 min and weighed to calculate the deposit mass. Each sample was tested in triplicate, and the results were expressed as the average deposit mass.

[0079] Electronic orifice fuel injector clogging tendency test: Following the evaluation criteria of GB / T 19230.3-2003, electronic orifice fuel injectors of the same manufacturer and model with an initial static flow deviation of less than 1.5% were selected, with six injectors per group. Before testing, the injection quality of each injector was tested for 30 seconds using base gasoline at a pressure of 300 kPa to obtain the initial static flow rate. Subsequently, each injector was run for 8 hours using gasoline with various additives at a pressure of 300 kPa, a pulse width of 2.5 ms, and a frequency of 10 Hz. During the operation, the fuel temperature was maintained at 40℃, and the ambient temperature was maintained at 25℃. After the operation, the injection quality was tested again for 30 seconds, and the flow rate decrease rate and the relative standard deviation of the flow rate within the group were calculated. The average value of the six injectors in each group was taken as the result for that sample.

[0080] Direct injection injector flow recovery rate test: The flow recovery of direct injection injectors was evaluated according to the injector testing methods in JB / T 12853.2-2016 and GB / T 25363-2010. Six direct injection injectors of the same manufacturer and model were selected in each group. They were first run for 8 hours with base gasoline at 18MPa rail pressure, 1.5ms pulse width, 10Hz frequency, and 85℃ fuel temperature. Then, they were hot-immersed in a 200℃ hot air chamber for 30 minutes. This cycle was repeated 8 times to reduce the static injection quality of each injector to 80%-82% of its initial value. After contamination, each injector was run for 2 hours with gasoline containing different additives at 18MPa rail pressure, 1.5ms pulse width, 10Hz frequency, and 85℃ fuel temperature, and then cooled to room temperature for 30 minutes. Before and after cleaning, fuel was continuously injected 1000 times at 25℃, 18MPa rail pressure, 1.5ms pulse width, and 10Hz frequency. The mass of injected fuel was weighed, and the flow recovery rate was calculated. The flow recovery rate was calculated using the formula: Flow recovery rate = (Injection mass after cleaning - Injection mass after contamination) / (Initial injection mass - Injection mass after contamination) × 100%. The average value of the flow rate was taken for each group of 6 injectors, and the relative standard deviation of the flow rate within the group was recorded.

[0081] Spray cone angle retention rate and atomization uniformity test: Using the same direct injection injectors as those used in the flow recovery rate test of direct injection injectors, spray images and particle size were measured in a transparent constant-temperature spray chamber. The spray chamber temperature was set to 25℃, back pressure to 0.10MPa, rail pressure to 18MPa, pulse width to 1.5ms, and injection frequency to 5Hz. A high-speed camera was used to acquire 20 consecutive spray images of each injector at 10,000 frames / s, and the spray cone angle was calculated from the image taken 1.5ms after each spray. A laser particle size analyzer was used to measure the Sotter mean diameter at a distance of 50mm below the nozzle. The spray cone angle retention rate was calculated using the formula: Spray cone angle retention rate = Spray cone angle after cleaning / Initial spray cone angle × 100%. Atomization uniformity was expressed as the relative standard deviation of the spray cone angle and the relative standard deviation of the Sotter mean diameter for 20 sprays. Six injectors were tested for each sample, and 20 spray data were collected for each injector, with the average value taken.

[0082] Table 1 Performance Test Results

[0083] sample Moisture, mg / kg Light transmittance at -20℃, % Simulated intake valve deposit mass, mg Electronic orifice nozzle flow rate reduction rate, % The flow rate RSD (%) within the electronic orifice nozzle assembly Flow recovery rate of in-cylinder direct injection injectors, % RSD of flow rate within the group after cleaning, % Spray cone angle retention rate, % Spray cone angle RSD, % Soter average diameter, μm Flow retention rate after hot immersion, % Spray cone angle retention rate after hot immersion, % B0 38 99.1 10.86 11.2 7.8 7.6 5.9 82.3 8.4 26.2 78.9 79.8 E1 116 98.2 0.86 1.5 1.2 89.2 0.9 96.4 1.2 18.3 95.7 94.8 E2 128 98.6 1.08 2.0 1.7 83.1 1.3 94.5 1.7 19.3 93.5 92.6 E3 119 98.7 0.72 1.2 1.0 91.8 0.7 97.2 1.0 17.9 96.2 95.4 E4 108 97.4 1.12 1.9 1.6 84.6 1.2 94.9 1.6 19.0 94.6 93.7 E5 102 96.8 1.34 2.3 1.9 80.4 1.5 93.8 1.9 19.7 92.8 91.9 E6 113 98.0 0.93 1.6 1.3 88.5 1.0 96.1 1.3 18.5 95.4 94.5 D1 318 72.6 5.86 7.8 5.6 36.8 4.5 87.1 5.8 23.8 85.6 84.0 D2 124 96.1 3.70 5.9 4.3 51.4 3.5 89.8 4.5 22.1 88.0 86.7 D3 138 95.1 2.86 4.8 3.7 58.6 2.9 91.2 3.8 21.3 89.3 88.2 D4 121 97.2 1.86 3.6 2.9 68.9 2.2 93.1 2.7 20.2 92.1 90.8 D5 104 98.1 5.21 6.8 5.0 32.7 4.8 86.5 6.1 24.6 84.2 83.1 D6 132 98.8 2.35 4.3 3.4 61.2 2.6 92.3 3.3 20.9 90.5 89.5 D7 148 91.8 2.58 5.2 3.8 63.5 2.7 91.8 3.5 21.4 88.9 87.6

[0084] As shown in Table 1, blank sample B0, without the addition of the fuel detergent composition, simulated intake valve deposit mass reached 10.86 mg, electronic nozzle flow rate decreased by 11.2%, and direct injection injector flow recovery rate was only 7.6%. Simultaneously, the spray cone angle retention rate after cleaning was low, and the average Sotter diameter was large, indicating that base gasoline alone has virtually no effective cleaning and recovery effect on the formed intake valve deposits and high-temperature coking layer of the direct injection injector. Compared with B0, the simulated intake valve deposit mass in Examples 1-6 was reduced to below 1.34 mg, the electronic nozzle flow rate decreased by no more than 2.3%, and the direct injection injector flow recovery rate increased to 80.4%-91.8%. Furthermore, the spray cone angle retention rate and the flow retention rate after hot soaking increased simultaneously, indicating that the fuel detergent composition obtained in this application can not only reduce the deposit tendency of the intake valve and electronic nozzle, but also improve the flow recovery and atomization consistency of the direct injection injector after contamination. Among them, Example 3 showed the best overall performance, with a simulated intake valve deposit mass of 0.72 mg, an electronic orifice nozzle flow rate decrease rate of 1.2%, a direct injection fuel injector flow recovery rate of 91.8%, a spray cone angle retention rate of 97.2%, and a Sotter average diameter reduced to 17.9 μm. This indicates that under the conditions of a number average molecular weight of approximately 1400, a relatively coordinated ratio of polyoxypropylene segments to polyoxyethylene enriched segments at the end of the chain, and the adjacency of the terminal primary amine to the terminal polar segment, the cleaning molecules have a more effective effect on the high-temperature metal surface and oxide deposit layer.

[0085] Comparative Example 1, lacking the introduction of a single-sided polyisobutylene end group, showed a significant decrease in low-temperature gasoline compatibility, resulting in weak detergency and recovery effects. Comparative Example 2, by altering the order of addition of ethylene oxide and propylene oxide, weakened the polar enrichment characteristics near the primary amine end, leading to a flow recovery rate of only 51.4% for the in-cylinder direct injection injector. Comparative Example 3, using a single addition of mixed epoxides, improved the flow rate reduction rate of the electronic orifice nozzle, but the simulated intake valve deposit quality and spray uniformity remained lower than the examples. Comparative Example 4, by adding all ethylene oxide after the propylene oxide reaction, retained a certain degree of end-polar chain segment effect, thus outperforming the other examples. While the number of comparative examples was lower, the flow recovery rate of the in-cylinder direct injection injectors was still lower than that of Examples 1-6, indicating that the two sequential additions of ethylene oxide to form a gentler chain-end polarity gradient has a positive effect on improving continuous cleaning and resistance to secondary deposition. Comparative Example 5 did not undergo catalytic amination and lacked terminal primary amine action sites, resulting in a significant increase in intake valve deposit quality, nozzle flow rate reduction rate, and Sotter average diameter. Comparative Examples 6 and 7 correspond to cases with low and high molecular weights, respectively. The former has insufficient high-temperature retention, while the latter is affected by low-temperature compatibility and micropore passage, thus neither can achieve the comprehensive effect of the examples.

[0086] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A fuel detergent composition, characterized in that, By mass, it includes 90-110 parts of graded polyetheramine main cleaning molecules, 70-90 parts of aromatic solvent oil and 1-3 parts of 2,6-di-tert-butyl-p-cresol; The gradient polyetheramine main cleaning molecule is obtained by hydroboration and oxidation of highly reactive polyisobutylene to form a monohydroxy polyisobutylene intermediate, followed by the sequential introduction of polyoxypropylene segments and polyoxyethylene enrichment segments at the end of the chain and the subsequent end-amination. The gradient polyetheramine main cleaning molecule has a single-sided polyisobutylene end group, a polyoxypropylene segment located between the single-sided polyisobutylene end group and the end-chain polyoxyethylene enrichment segment, and a terminal primary amine adjacent to the end-chain polyoxyethylene enrichment segment. The chain-end polyoxyethylene enrichment segment is formed by adding ethylene oxide in two separate steps after the residual amount of propylene oxide is less than 2 g / kg. Based on mass parts, the gradient polyetheramine main cleaning molecule is obtained by ring-opening reaction of 140-160 parts of monohydroxy polyisobutylene intermediate, 32-48 parts of propylene oxide, 3-5 parts of the first part of ethylene oxide, and 6-10 parts of the second part of ethylene oxide to form a gradient polyether alcohol intermediate, followed by catalytic amination; the number average molecular weight of the gradient polyether alcohol intermediate is 1300-1600, and the hydroxyl value is 36-43 mg KOH / g; The ring-opening reaction comprises: forming a polyisobutylene alkoxide starting seed by reacting the monohydroxy polyisobutylene intermediate in the presence of 35-45 parts anhydrous toluene, 15-25 parts anhydrous tetrahydrofuran, 4-6 parts 18-crown ether-6, and 1.5-2.5 parts potassium tert-butoxide, by mass; adding propylene oxide to the polyisobutylene alkoxide starting seed and reacting until the residual propylene oxide is less than 2 g / kg; then adding a first part of ethylene oxide and reacting until the residual ethylene oxide is less than 2 g / kg; then adding a second part of ethylene oxide and reacting until the residual ethylene oxide is less than 2 g / kg; and finally adding 1.5-2.5 parts of glacial acetic acid for neutralization to obtain a gradient polyether alcohol intermediate; The gradient polyetheramine main cleaning molecules have a number average molecular weight of 1300-1600 and a total amine value of 35-44 mg KOH / g.

2. The fuel detergent composition according to claim 1, characterized in that, The highly reactive polyisobutylene has a number average molecular weight of 1000 and a molar content of 87.4% of terminal vinylidene double bonds.

3. The fuel detergent composition according to claim 1, characterized in that, The monohydroxy polyisobutylene intermediate is obtained by reacting 180-220 parts of highly reactive polyisobutylene, 108-132 parts of a 2 mol / L solution of borane dimethyl sulfide complex tetrahydrofuran, 14-18 parts of sodium hydroxide, 126-150 parts of deionized water, and 90-110 parts of a 30% hydrogen peroxide solution in 360-440 parts of anhydrous n-hexane, by mass fraction.

4. The fuel detergent composition according to claim 1, characterized in that, Based on mass parts, in the catalytic amination, for every 100 parts of gradient polyether alcohol intermediate, the amount of Raney nickel catalyst is 10-14 parts, the amount of anhydrous liquid ammonia is 50-70 parts, the hydrogen pressure is 5-7 MPa, the catalytic amination temperature is 210-230℃, and the catalytic amination time is 6-10 h; the hydroxyl value of the main clean molecule of the gradient polyether amine obtained by catalytic amination is 2.5-4 mg KOH / g.

5. The fuel detergent composition according to claim 1, characterized in that, The fuel detergent composition, by weight, is a mixture of 100 parts of gradient polyetheramine main detergent molecules, 80 parts of aromatic solvent oil, and 2 parts of 2,6-di-tert-butyl-p-cresol.

6. The fuel detergent composition according to claim 1, characterized in that, The aromatic solvent oil is a C9-C12 high-boiling-point aromatic solvent oil with a closed-cup flash point of not less than 60℃.

7. A method for preparing a fuel detergent composition according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Highly reactive polyisobutylene is subjected to hydroboration and oxidation reactions to obtain monohydroxy polyisobutylene intermediate; (2) After the monohydroxy polyisobutylene intermediate is converted into polyisobutylene alkoxide starting seed, propylene oxide is added first to react. After the residual propylene oxide is less than 2 g / kg, the first part of ethylene oxide and the second part of ethylene oxide are added in sequence to react and obtain gradient polyether alcohol intermediate. (3) The gradient polyether alcohol intermediate is subjected to catalytic amination with anhydrous liquid ammonia and hydrogen in the presence of Raney nickel catalyst to obtain the gradient polyether amine main clean molecule; (4) The gradient polyetheramine main cleaning molecule, aromatic solvent oil and 2,6-di-tert-butyl-p-cresol are mixed and filtered to obtain a fuel cleaning agent composition.

8. The method for preparing the fuel detergent composition according to claim 7, characterized in that, In step (4), mixing and filtering are performed by stirring at 300 r / min for 1 h at 50 °C and then filtering through a 5 μm filter.