Preparation method of amphiphilic carbon dots, amphiphilic carbon dots and application of amphiphilic carbon dots

Abstract

The invention discloses a preparation method of an amphiphilic carbon dot, the amphiphilic carbon dot and application of the amphiphilic carbon dot. According to the amphiphilic carbon dots, at least one of phenol, catechol, resorcinol or hydroquinone is used as a first precursor, and at least one of urea, aniline, o-phenylenediamine or 1, 2, 4-triaminobenzene is selected as a second precursor; after mixing and dissolving, reacting for 4-8 hours under the condition of 180-220 DEG C to prepare initial carbon dots; separating and purifying the initial carbon dots in a chromatographic column, collecting a second component, removing the solvent through rotary evaporation, and drying to obtain the amphiphilic carbon dots. The degreasing agent prepared from the obtained amphiphilic carbon dots has strong adsorption capacity, low toxicity and good stability, can effectively remove oil stains, has the characteristic of low foam in the use process, simplifies the cleaning process and improves the efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of application of functional nanomaterials in daily chemicals, and in particular to a preparation method of amphiphilic carbon dots, amphiphilic carbon dots and applications thereof. Background Art

[0002] The commonly used degreasing agent on the market is mainly composed of surfactants and builders. The hydrophilic group and lipophilic group in the surfactant molecule are adsorbed at the interface between the oil stain and the solution to reduce the oil-liquid interfacial tension and achieve the removal of the oil stain. However, the conventional surfactants such as alkylphenol polyoxyethylene ether and sodium alkylbenzene sulfonate are effective, but they will produce a large amount of foam, increase the difficulty of rinsing and cause stains to remain, thereby causing material waste and rising cleaning costs. In addition, although low-foam surfactants can reduce foam generation, their cleaning effects are relatively poor. Although commonly used alkaline builders such as sodium hydroxide, soda ash, sodium silicate and sodium tripolyphosphate are helpful to enhance cleaning ability, the waste water generated is difficult to handle, and the strong alkalinity may damage the surface of the object to be cleaned, and is accompanied by irritating odor.

[0003] In view of the above problems, it is particularly important to develop an environmentally friendly and efficient degreasing agent. Summary of the invention

[0004] In order to solve at least one of the above technical problems and develop an oil remover with good oil removal effect and environmental protection and safety, the present application provides a preparation method of amphiphilic carbon dots, amphiphilic carbon dots and applications thereof.

[0005] In a first aspect, the present application provides a method for preparing amphiphilic carbon dots, the preparation method comprising the following steps: S1, selecting at least one of phenol, catechol, resorcinol or hydroquinone as a first precursor, and selecting at least one of urea, aniline, o-phenylenediamine or 1,2,4-triaminobenzene as a second precursor; S2, mixing the first precursor and the second precursor, dissolving them in N,N-dimethylformamide, transferring the resulting solution to a reaction kettle, and reacting them at 180-220° C. for 4-8 hours to obtain initial carbon dots; S3. Using a mixed solvent of dichloromethane and methanol as an eluent, the initial carbon dots are separated and purified in a chromatography column, and the second component in the purification process is collected. After removing the solvent by rotary evaporation and drying, the amphiphilic carbon dots are obtained.

[0006] By adopting the above technical scheme, the amphiphilic carbon dots provided by the present application have the advantages of strong adsorption, low toxicity, good stability, etc. The amphiphilic carbon dots provided by the present application can solve the problems of insufficient degreasing strength and high degreasing cost in the degreasing agent prepared by surfactant in the prior art, and can also avoid the problem of wastewater generated by alkaline detergents during the degreasing process. It has the advantages of safety, environmental protection, stability and good degreasing effect.

[0007] In the process of preparing amphiphilic carbon dots, the first precursor and the second precursor react chemically under high temperature to generate initial carbon dots. Since the prepared amphiphilic carbon dots have nanometer size, they have a large specific surface area and high surface energy. This characteristic makes the carbon dots have strong adsorption. In addition, when preparing amphiphilic carbon dots, the present application can better regulate the surface properties of amphiphilic carbon dots, such as polarity, charge density, etc., by selecting different precursors and reaction conditions, so as to improve the oil removal efficiency. At the same time, when preparing amphiphilic carbon dots, the present application uses organic precursors instead of traditional surfactants or alkaline builders, so that this method avoids the problem of generating wastewater and environmental pollution. At the same time, due to the low toxicity and stability of carbon dots, this method has the advantages of safety and environmental protection. And it has higher efficiency and lower cost. In summary, the preparation method of amphiphilic carbon dots provided by the present application, based on chemical reaction principles, nanometer size effect, surface property regulation, environmental protection and safety, and oil removal mechanism, achieves high efficiency, low cost, environmentally safe oil removal effect.

[0008] Optionally, the molar ratio of the first precursor to the second precursor in step S1 is (2.2-1.2):1.

[0009] By adopting the above technical scheme, the present application proposes a method for preparing amphiphilic carbon dots, wherein in step S1, the molar ratio of the first precursor to the second precursor is preferably (2.2-1.2): 1. This optimized molar ratio helps to promote the effective progress of the chemical reaction under high temperature conditions and generate initial carbon dots with specific properties. Since these carbon dots are nanosized, they have a large specific surface area and a high surface energy, and therefore have excellent adsorption capacity. In addition, by selecting different precursors and adjusting the reaction conditions, the surface properties of the amphiphilic carbon dots, including polarity and charge density, can be better controlled, thereby further improving the oil removal efficiency. The method of preparing carbon dots using organic precursors avoids the wastewater problems and environmental pollution caused by traditional surfactants or alkaline builders, and the low toxicity and stability of the carbon dots themselves ensure the safety and environmental protection of the entire process. In addition, the carbon dots provided in the present application show higher efficiency and lower cost. In summary, the method for preparing amphiphilic carbon dots proposed in the present application utilizes precise chemical reaction principles, nanosize effects, surface property regulation, and environmental protection and safety considerations to achieve an efficient, economical and environmentally friendly oil removal solution.

[0010] Optionally, the volume ratio of dichloromethane to methanol in step S3 is 6:1.

[0011] By adopting the above technical solution, the present application can effectively achieve the separation and purification of initial carbon dots by selecting dichloromethane and methanol as eluents and adjusting their volume ratio, thereby improving the purity and yield of carbon dots. This technical solution is suitable for the separation and purification process of carbon dots in large-scale preparation and production. Moreover, compared with some harmful organic solvents, dichloromethane and methanol have relatively low toxicity, are easy to recycle and handle, and are environmentally friendly.

[0012] Optionally, before the initial carbon dots are separated and purified by a chromatography column, the initial carbon dots need to be mixed with silica gel powder and dichloromethane and stirred evenly, and then the solvent is removed by reduced pressure distillation.

[0013] By adopting the above technical scheme, before using the chromatography column for separation and purification, the initial carbon dots are first mixed with silica gel powder and dichloromethane and stirred evenly, and then the solvent is removed by vacuum distillation. This pretreatment step helps to remove impurities that may be introduced during the preparation process, and the initial carbon dots can be effectively concentrated and purified by the adsorption of silica gel powder and the solubility of dichloromethane. Vacuum distillation can remove the solvent at a lower temperature, avoiding the potential damage of high temperature to the carbon dot structure, thereby ensuring the purity and quality of the final product. This series of operations not only improves the efficiency and purity of subsequent chromatography column separation and purification, but also ensures that the obtained amphiphilic carbon dots have the advantages of strong adsorption, low toxicity, good stability, etc., thereby solving the problem of insufficient degreasing strength and high degreasing cost of degreasing agents in the prior art, and avoiding the wastewater problem generated by the use of alkaline detergents. In summary, the amphiphilic carbon dot preparation method provided by the present application achieves a high-efficiency, low-cost, environmentally friendly and safe degreasing effect through chemical reaction principles, nano-size effects, surface property regulation, environmental protection and safety, and degreasing mechanisms.

[0014] In a second aspect, the present application provides an amphiphilic carbon dot, which is prepared by the preparation method provided by the present application.

[0015] In a third aspect, the present application provides an application of amphiphilic carbon dots prepared by the preparation method provided by the present application in the field of degreasing agents.

[0016] By adopting the above technical scheme, the amphiphilic carbon dots provided by the present application can be used in the field of preparing degreasing agents, with better degreasing effect, and the ingredients have the advantages of safety and environmental protection. Specifically, as follows: First, amphiphilic carbon dots can effectively remove oil stains due to their special surface properties and adsorption capacity. Second, the amphiphilic carbon dots themselves are prepared from environmentally friendly raw materials and do not contain toxic and harmful substances. In the degreasing process, they do not produce wastewater or harmful substances and are environmentally friendly. In addition, due to their low toxicity and stability, they are also harmless to the human body when used. Third, amphiphilic carbon dots can be used for different types of oil removal, such as mineral oil, animal and vegetable oils, etc. They are not affected by factors such as water hardness and pH value, and have a wider range of applications. Fourth, amphiphilic carbon dots can be reused after proper treatment, reducing the cost of use. This also helps to reduce the generation of waste and achieve sustainable development. Fifth, the preparation method of amphiphilic carbon dots is relatively simple and easy to achieve large-scale production and application. This helps to reduce the cost of degreasing agents and make them more competitive in the market. In summary, the application of the amphiphilic carbon dots provided in this application in the field of oil removal has the advantages of high efficiency, environmental safety, strong adaptability, reusability and versatility. This technical solution provides a new and environmentally friendly solution for the oil removal field, which helps to promote technological progress and application expansion in related industries.

[0017] In a fourth aspect, the present application provides a degreasing agent, wherein the degreasing agent is prepared from the amphiphilic carbon dots prepared by the preparation method of amphiphilic carbon dots provided by the present application.

[0018] In a fifth aspect, the present application provides a method for preparing a degreasing agent, the preparation method comprising the following steps: The amphiphilic carbon dots are dissolved in water to prepare a degreasing agent, wherein the weight ratio of the amphiphilic carbon dots to the water is (5-7):1.

[0019] By adopting the above technical solution, the degreasing agent preparation method provided by the present application is simple, environmentally friendly, can be mass-produced and has a good degreasing effect. This technical solution is suitable for oil removal in industrial production and daily life, and helps to promote technological progress and application expansion in related industries.

[0020] In summary, the present invention includes at least one of the following beneficial technical effects: 1. The amphiphilic carbon dots provided by the present application have the advantages of strong adsorption, low toxicity, good stability, etc. The amphiphilic carbon dots provided by the present application can solve the problems of insufficient degreasing strength and high degreasing cost in the degreasing agent prepared by surfactants in the prior art, and can also avoid the problem of wastewater generated by alkaline detergents during the degreasing process. It has the advantages of safety, environmental protection, stability and good degreasing effect. In the process of preparing the amphiphilic carbon dots in the present application, the first precursor and the second precursor react chemically under high temperature conditions to generate initial carbon dots. Since the prepared amphiphilic carbon dots have nanometer size, they have a large specific surface area and a high surface energy. This characteristic makes the carbon dots have strong adsorption. In addition, when preparing the amphiphilic carbon dots, the present application can better regulate the surface properties of the amphiphilic carbon dots, such as polarity, charge density, etc., by selecting different precursors and reaction conditions, so as to better improve the degreasing efficiency. At the same time, when preparing amphiphilic carbon dots, the present application uses organic precursors instead of traditional surfactants or alkaline builders, so this method avoids the problem of generating wastewater and environmental pollution. At the same time, due to the low toxicity and stability of carbon dots, this method has the advantages of safety and environmental protection. And it has higher efficiency and lower cost. In summary, the preparation method of amphiphilic carbon dots provided by the present application, based on chemical reaction principles, nano-size effects, surface property regulation, environmental protection and safety, and oil removal mechanisms, achieves a high-efficiency, low-cost, environmentally friendly and safe oil removal effect.

[0021] 2. The amphiphilic carbon dots provided in this application can be used in the field of preparing degreasing agents, with good degreasing effects, and the ingredients have the advantages of safety and environmental protection. Specifically, as follows: First, amphiphilic carbon dots can effectively remove oil stains due to their special surface properties and adsorption capacity. They can physically or chemically adsorb with oil stains, thereby achieving the effect of rapid degreasing. Second, the amphiphilic carbon dots themselves are prepared from environmentally friendly raw materials and do not contain toxic and harmful substances. In the degreasing process, they do not produce wastewater or harmful substances and are environmentally friendly. In addition, due to their low toxicity and stability, they are also harmless to the human body when used. Third, amphiphilic carbon dots can be used for different types of oil removal, such as mineral oil, animal and vegetable oils, etc. They are not affected by factors such as water hardness and pH value, and have a wide range of applications. Fourth, amphiphilic carbon dots can be reused after proper treatment, reducing the cost of use. This also helps to reduce the generation of waste and achieve sustainable development. Fifth, the preparation method of amphiphilic carbon dots is relatively simple and easy to achieve large-scale production and application. This helps to reduce the cost of degreasing agents and make them more competitive in the market. In summary, the application of the amphiphilic carbon dots provided in this application in the field of oil removal has the advantages of high efficiency, environmental safety, strong adaptability, reusability and versatility. This technical solution provides a new and environmentally friendly solution for the oil removal field, which helps to promote technological progress and application expansion in related industries.

[0022] 3. The degreasing agent preparation method provided in this application is simple, environmentally friendly, can be mass-produced and has a good degreasing effect. This technical solution is suitable for oil removal in industrial production and daily life, and helps to promote technological progress and application expansion in related industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 , Figure 1 This is a graph showing the results of the carbon dot extraction experiment in Preparation Example 1. The carbon dot aqueous solution was dispersed in toluene, and the solution was separated into layers. The left side is a photo taken under sunlight, and the right side is a photo taken under ultraviolet light. It can be seen that the carbon dots are dispersed in both water and toluene, and both phases have fluorescence, indicating that the carbon dots are amphiphilic. Figure 2 , Figure 2 The upper part and the lower part are the front view and the side view of the amount of residual oil on the glass test piece taken at 5 minutes and 15 minutes respectively when the carbon dot solution and the commercial degreasing agent in Example 1 and Comparative Example 1 remove 30 mg of dimethyl silicone oil; Figure 3 , Figure 3 The upper part and the lower part are the front view and the side view of the amount of residual oil on the glass test piece taken at 5 minutes and 15 minutes respectively when the carbon dot solution and the commercial degreasing agent in Example 2 and Comparative Example 2 remove 10 mg of soybean oil; Figure 4 , Figure 4 The upper part and the lower part are the front view and the side view of the amount of residual oil on the glass test piece taken at 2 minutes and 5 minutes respectively when the carbon dot solution and the commercial degreasing agent in Example 3 and Comparative Example 3 remove 1 mg of vacuum pump oil; Figure 5 , Figure 5 This is a graph showing the results of the carbon dot extraction experiment in Preparation Example 2. The carbon dot aqueous solution was dispersed in toluene, and the solution was separated into layers. The left side is a photo taken under sunlight, and the right side is a photo taken under ultraviolet light. It can be seen that the carbon dots are only dispersed in the lower layer of water, and there is fluorescence in the aqueous phase, indicating that the carbon dots are hydrophilic. Figure 6 , Figure 6 This is a diagram showing the oil removal effect of the hydrophilic carbon dots of Comparative Example 4; Figure 7 , Figure 7 This is a graph showing the results of the carbon dot extraction experiment prepared in Preparation Example 3. The carbon dot aqueous solution was dispersed in toluene, and the solution was separated into layers. The left side is a photo taken under sunlight, and the right side is a photo taken under ultraviolet light. It can be seen that the carbon dots are only dispersed in the upper layer of toluene, and there is fluorescence in the oil phase, indicating that the carbon dots are hydrophobic. Figure 8 , Figure 8 This is a diagram showing the oil removal effect of the hydrophobic carbon dots in comparative example 5. DETAILED DESCRIPTION

[0024] The present application is further described in detail below with reference to the accompanying drawings and embodiments.

[0025] The following are the sources of the raw materials used in this application: Phenol: CAS number is 108-95-2, purity is 99.9%; Catechol: CAS number is 120-80-9, purity is 99%; Resorcinol: CAS number is 108-46-3, purity is 99.9%; Hydroquinone: CAS number is 123-31-9, purity is 99.95%; Urea: purity 99%; Aniline: CAS number is 62-53-3, purity is 99%; o-Phenylenediamine: CAS number is 95-54-5, purity is 99%; 1,2,4-Triaminobenzene: CAS number is 615-47-4, purity is 98%; Dichloromethane: CAS number is 75-09-2, purity is 99.9%; Methanol: CAS number is 67-56-1, purity is 99.8%.

[0026] Preparation Example 1 This preparation example provides an amphiphilic carbon dot, and the preparation method comprises the following steps: Weigh 1g of catechol (the first precursor) and 0.33g of urea (the second precursor), dissolve them in N,N-dimethylformamide, and heat them to 210°C in a reactor for 6 hours. After the reaction is completed, cool to room temperature, stir the carbonized mixture obtained by the reaction with a certain mass of silica gel powder and an appropriate amount of dichloromethane, remove the solvent by vacuum distillation, purify it by column chromatography with dichloromethane and methanol as eluents (the volume ratio of dichloromethane to methanol is 6:1), collect the second component solution, perform vacuum distillation, and then freeze-dry to obtain carbon dot powder.

[0027] The amphiphilicity of the carbon dots in this preparation example is as follows Figure 1 shown.

[0028] Preparation Example 2 The difference between this preparation example and preparation example 1 is that the preparation in this example is as follows: Weigh 1.316g of phenol (first precursor) and 1.08g of o-phenylenediamine (second precursor), dissolve them in N,N-dimethylformamide, and heat to 180°C in a reactor for 8h. After the reaction is completed, cool to room temperature, stir the initial carbon dots obtained by the reaction with silica gel powder and dichloromethane, remove the solvent by vacuum distillation, purify it by column chromatography with dichloromethane and methanol as eluents (the volume ratio of dichloromethane to methanol is 6:1), collect the second component solution, perform vacuum distillation and further freeze-dry to obtain carbon dot powder.

[0029] Preparation Example 3 The difference between this preparation example and preparation example 1 is that the preparation in this example is as follows: Weigh 1g of catechol (the first precursor) and 1.078g of 1,2,4-triaminobenzene (the second precursor), dissolve them in N,N-dimethylformamide, and heat them to 220℃ in a reactor for 4h. After the reaction is completed, cool to room temperature, stir the carbonized mixture obtained by the reaction with a certain mass of silica gel powder and an appropriate amount of dichloromethane, remove the solvent by vacuum distillation, and purify it by column chromatography with dichloromethane and methanol as eluents. The volume ratio of dichloromethane to methanol is 6:1. Collect the second component solution, distill it under reduced pressure, and further freeze-dry it to obtain carbon point powder.

[0030] The following are specific embodiments Example 1: Experiment on removing dimethyl silicone oil; Preparation of degreasing agent: 150 mg of carbon dots (carbon dot powder prepared in Preparation Example 1) was dissolved in 30 ml of water to prepare a carbon dot solution (ie, the degreasing agent).

[0031] The oil removal test is as follows: Preparation of test piece: Use glass piece with specification of 1.5cm×7cm and oil loading area of ​​10cm 2 The oil loading amount is 30 mg, and the loaded oil type is dimethyl silicone oil.

[0032] Weigh the test piece on the analytical balance as M, evenly smear the weighed test piece with oil, and weigh the test piece after natural air drying for 10 hours as M1. Put the air-dried oil piece into a centrifuge tube, and then put it into a shaker at a shaking rate of 200r / min. Observe the removal of oil on the surface of the glass piece at 5min and 15min respectively. The test piece after oil removal is weighed as M2.

[0033] The calculation formula for the oil removal rate is [(M1M2) / (M1M)]×100%.

[0034] The final oil removal rate of the treatment in this example was calculated to be 95.7% (oil removal rate at 15 minutes).

[0035] Comparative Example 1 A commercially available degreasing agent was taken as a control group (as comparative example 1, the model was Snow Leopard Grenade), and the degreasing experimental operation steps were the same as those in Example 1. The final degreasing rate was calculated to be 83% (the degreasing rate at 15 minutes).

[0036] See the oil removal effect diagram of the oil removal agent prepared in Example 1 and Comparative Example 1. Figure 2 .

[0037] Figure 2 The front and side views of the amount of residual oil on the glass specimen taken at 5 min and 15 min, respectively, when the carbon dot solution and commercial degreasing agent were removing 30 mg of dimethyl silicone oil.

[0038] The differences between Example 1 and Comparative Example 1 and the experimental results are shown in Table 1.

[0039] Table 1 - Differences between Example 1 and Comparative Example 1 and experimental results Result analysis: The degreasing effects of Example 1 and Comparative Example 1 are as follows Figure 2 As shown, it can be seen intuitively that the removal effect of the carbon dot solution is better than that of the commercial degreasing agent.

[0040] Example 2, soybean oil removal experiment; Preparation of degreasing agent: Dissolve 150 mg of carbon dots (the carbon dots prepared in Preparation Example 1) in 30 ml of water to prepare a carbon dot solution.

[0041] The oil removal test is as follows: Preparation of test piece: Use glass piece with specification of 1.5cm×7cm and oil loading area of ​​10cm 2 The oil loading amount is 10 mg, and the loaded oil type is soybean oil.

[0042] Weigh the test piece on the analytical balance as M, evenly smear the weighed test piece with oil, and weigh the test piece after natural air drying for 10 hours as M1. Put the air-dried oil piece into a centrifuge tube, and then put it into a shaker at a shaking rate of 200r / min. Observe the removal of oil on the surface of the glass piece at 5min and 15min respectively. The test piece after oil removal is weighed as M2.

[0043] The calculation formula for the oil removal rate is [(M1M2) / (M1M)]×100%.

[0044] The final oil removal rate of the treatment in this example was calculated to be 99.4% (removal rate at 15 min).

[0045] Comparative Example 2 A commercially available degreasing agent was taken as a control group (as comparative example 2, the model was Snow Leopard Grenade), and the degreasing experimental operation steps were the same as those in Example 2. The final degreasing rate was calculated to be 98.4% (removal rate at 15 min).

[0046] See the oil removal effect diagram of the oil removal agent prepared in Example 2 and Comparative Example 2. Figure 3 .

[0047] Figure 3 The front and side views of the amount of residual oil on the glass specimen taken at 5 min and 15 min, respectively, when the carbon dot solution and commercial degreasing agent removed 10 mg of soybean oil.

[0048] The differences between Example 2 and Comparative Example 2 and the experimental results are shown in Table 2.

[0049] Table 2 - Differences between Example 2 and Comparative Example 2 and experimental results Result analysis: The degreasing effects of Example 2 and Comparative Example 2 are as follows: Figure 3 As shown, it can be seen intuitively that the removal effect of the carbon dot solution is better than that of the commercial degreasing agent.

[0050] Example 3: Soybean oil removal experiment Preparation of degreasing agent: Dissolve 150 mg of carbon dots (prepared in Preparation Example 1) in 30 ml of water to prepare a carbon dot solution.

[0051] The oil removal test is as follows: Preparation of test piece: Use glass piece with specification of 1.5cm×7cm and oil loading area of ​​10cm 2The oil loading amount is 1 mg, and the loaded oil type is soybean oil.

[0052] Weigh the test piece on the analytical balance as M, evenly smear the weighed test piece with oil, and weigh the test piece after natural air drying for 10 hours as M1. Put the air-dried oil piece into a centrifuge tube, and then put it into a shaker at a shaking rate of 200r / min. Observe the removal of oil on the surface of the glass piece at 2min and 5min respectively. The test piece after oil removal is weighed as M2.

[0053] The calculation formula for the oil removal rate is [(M1M2) / (M1M)]×100%.

[0054] The final oil removal rate of the treatment in this example was calculated to be 88.4% (removal rate at 5 minutes).

[0055] Comparative Example 3 A commercially available degreasing agent was taken as a control group (as comparative example 3, the model was Snow Leopard Grenade), and the degreasing experimental operation steps were the same as those in Example 3. The final degreasing rate was calculated to be 82.7% (removal rate at 5 minutes).

[0056] The degreasing effects of the two are as follows Figure 4 As shown, it can be seen intuitively that the removal effect of the carbon dot solution is better than that of the commercial degreasing agent.

[0057] Figure 4 The front and side views of the amount of residual oil on the glass specimen taken at 2 min and 5 min, respectively, when the carbon dot solution and commercial degreasing agent removed 1 mg of soybean oil.

[0058] The differences between Example 3 and Comparative Example 3 and the experimental results are shown in Table 2.

[0059] The differences between Example 3 and Comparative Example 3 and the experimental results are shown in Table 3.

[0060] Table 3 - Differences between Example 3 and Comparative Example 3 and experimental results Example 4: Experiment on removing dimethyl silicone oil; Preparation of degreasing agent: Dissolve 150 mg of carbon dots (prepared in Preparation Example 2) in 30 ml of water to prepare a carbon dot solution.

[0061] Oil removal experiment: A glass sheet with a size of 1.5 cm × 7 cm was used, and the oil loading area was 10 cm 2The oil loading amount is 30 mg, and the loading oil type is dimethyl silicone oil. The air-dried oil piece is placed in a centrifuge tube, and then placed in a shaker with a shaking rate of 200 r / min. The oil removal on the surface of the glass piece is observed at 5 minutes and 15 minutes respectively, and the final oil removal rate is calculated to be 96.4% (oil removal rate at 15 minutes).

[0062] Comparative Example 4 The difference between this comparative example and Example 4 is that the preparation method of the carbon dots in this comparative example is as follows: Weigh 1.316g of phenol (first precursor) and 1.08g of o-phenylenediamine (second precursor), dissolve them in N,N-dimethylformamide, and heat to 240°C in a reactor for 6 hours. After the reaction is completed, cool to room temperature, stir the initial carbon dots obtained by the reaction with silica gel powder and dichloromethane, remove the solvent by vacuum distillation, and purify it by column chromatography with dichloromethane and methanol as eluents (the volume ratio of dichloromethane to methanol is 4:1), collect the second component solution, perform vacuum distillation, and further freeze-dry to obtain a hydrophilic light blue carbon dot powder.

[0063] The hydrophilicity of the carbon dots in this comparative example is as follows Figure 5 shown.

[0064] The differences between Example 4 and Comparative Example 4 and the experimental results are shown in Table 4.

[0065] Table 4 Differences between Example 4 and Comparative Example 4 and experimental results Result analysis: Since the carbon dots in this comparative example are only hydrophilic, the prepared carbon dot aqueous solution has no degreasing effect. For the degreasing effect diagram of this comparative example, see Figure 6 .

[0066] Example 5: Experiment on removing dimethyl silicone oil Preparation of degreasing agent: Dissolve 150 mg of carbon dots (prepared in Preparation Example 3) in 30 ml of water to prepare a carbon dot solution.

[0067] Oil removal experiment: A glass sheet with a size of 1.5 cm × 7 cm was used, and the oil loading area was 10 cm 2 , the oil loading amount is 30mg, and the loaded oil type is dimethyl silicone oil. The air-dried oil piece is placed in a centrifuge tube, and then placed in a shaker with a shaking rate of 200r / min. The oil removal on the surface of the glass piece is observed at 5min and 15min respectively, and the final oil removal rate is calculated to be 98.9% (oil removal rate at 15min).

[0068] Comparative Example 5 Weigh 1g of catechol and 1.078g of 1,2,4-triaminobenzene, dissolve them in N,N-dimethylformamide, and heat them to 160°C in a reactor for 6 hours. After the reaction is completed, cool to room temperature, stir the carbonized mixture obtained by the reaction with a certain mass of silica gel powder and an appropriate amount of dichloromethane, remove the solvent by vacuum distillation, and purify it by column chromatography using dichloromethane and methanol as eluents. The volume ratio of dichloromethane to methanol is 4:1. Collect the second component solution, perform vacuum distillation, and further freeze-dry to obtain lipophilic orange-red carbon dot powder.

[0069] The hydrophobicity of the carbon dots prepared in this comparative example is as follows Figure 7 shown.

[0070] The differences between Example 5 and Comparative Example 5 and the experimental results are shown in Table 5.

[0071] Table 5 - Differences between Example 5 and Comparative Example 5 and experimental results Result analysis: Since carbon dots are only hydrophobic, the prepared carbon dot aqueous solution has no degreasing effect. For the degreasing effect diagram of this comparative example, see Figure 8 .

[0072] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing amphiphilic carbon dots, characterized in that: The preparation method comprises the following steps: S1, selecting at least one of phenol, catechol, resorcinol or hydroquinone as the first precursor, and selecting at least one of urea, aniline, o-phenylenediamine or 1,2,4-triaminobenzene as the second precursor; S2, mixing the first precursor and the second precursor, dissolving them in N,N-dimethylformamide, and transferring the resulting solution to a reaction kettle, reacting at 180-220° C. for 4-8 hours to obtain initial carbon dots; S3. Using a mixed solvent of dichloromethane and methanol as an eluent, the initial carbon dots are separated and purified in a chromatography column, and the second component in the purification process is collected. After removing the solvent by rotary evaporation and drying, the amphiphilic carbon dots are obtained.

2. The method for preparing amphiphilic carbon dots according to claim 1, characterized in that: The molar ratio of the first precursor to the second precursor in step S1 is (2.2-1.2):

1.

3. The method for preparing amphiphilic carbon dots according to claim 1, characterized in that: The volume ratio of dichloromethane to methanol in step S3 is 6:

1.

4. The method for preparing amphiphilic carbon dots according to claim 1, characterized in that: Before the initial carbon dots are separated and purified by chromatography, they need to be mixed with silica gel powder and dichloromethane and stirred evenly, and then the solvent is removed by reduced pressure distillation.

5. An amphiphilic carbon dot, characterized in that: The amphiphilic carbon dots are prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the amphiphilic carbon dots prepared according to any one of claims 1 to 4 in the field of degreasing agents.

7. A degreasing agent, characterized in that: The degreasing agent is prepared from the amphiphilic carbon dots prepared by the preparation method of amphiphilic carbon dots according to claim 1.

8. A method for preparing a degreasing agent, characterized in that: The preparation method comprises the following steps: dissolving the amphiphilic carbon dots in water to prepare a degreasing agent, wherein the weight ratio of the amphiphilic carbon dots to the water is (5-7):1.

Images