Preparation method of Gemini type surfactant with pH responsiveness
By preparing a Gemini type surfactant with pH responsiveness, the problem of limited effects of traditional surfactants on the liquid surface is solved, and the effect of significantly enhancing the surface tension and emulsification ability of the liquid is achieved.
Patent Information
- Application Number
- CN202411636050.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-15
- Publication Date
- 2025-02-25
AI Technical Summary
The traditional single-head and single-tail structure surfactants have limited effects on the liquid surface, making it difficult to effectively enhance the surface tension and emulsification ability of the liquid.
Using a method of preparing a Gemini type surfactant with pH responsiveness, a multi-step reaction is carried out under an inert atmosphere, including the formation of an aromatic halogenated hydrocarbon containing aldehyde groups and the reaction with a tertiary amine to form a bi-headed hydrophilic precursor. And react with primary amine to form Gemini surfactant.
The prepared Gemini type surfactant has good pH response, can greatly enhance the surface tension of the liquid, and has good emulsification ability, and controls the emulsification behavior of the emulsion by regulating the pH.
Smart Images
Figure BDA0005137175740000041 
Figure BDA0005137175740000051 
Figure BDA0005137175740000052
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of surfactants, and in particular to a method for preparing a Gemini surfactant with pH responsiveness. Background Art
[0002] Quaternary ammonium salt surfactants are a common cationic surfactant, which are formed by the alkylation reaction of tertiary amines and halogenated hydrocarbons to form surfactants with a hydrophilic head and a hydrophobic tail.
[0003] The imine bond is one of the most common dynamic covalent bonds in the field of organic chemistry. It is generated by the Schiff base reaction between the aldehyde group and the primary amine group. It is stable in an alkaline environment, dissociates in an acidic environment, and is pH responsive. Traditional surfactants have a single head and a single tail structure, and their effect on the surface tension of liquids is relatively limited. If a double-headed and double-tailed surfactant can be generated by reaction, its surface effect will be greatly enhanced. Summary of the invention
[0004] The purpose of the present invention is to provide a method for preparing a Gemini-type surfactant with pH responsiveness. The prepared Gemini-type surfactant has good pH responsiveness, can greatly enhance the surface tension of the liquid, and also has good emulsifying ability, and the demulsification behavior of the emulsion can be controlled by regulating the pH.
[0005] To achieve the above object, the present invention provides a method for preparing a Gemini surfactant with pH responsiveness, comprising the following steps:
[0006] S1. Under an inert atmosphere, potassium carbonate and 1,2-dibromoethane are added to a three-necked flask and dissolved in acetonitrile. The mixture is heated and stirred continuously. p-hydroxybenzaldehyde is dissolved in acetonitrile and then slowly dripped into the three-necked flask. The mixed solution is continuously heated. After cooling to room temperature, the mixture is filtered. The filtrate is separated and purified by column chromatography, and then rotary evaporated and dried in a vacuum drying oven to obtain an aldehyde-containing aromatic halogenated hydrocarbon.
[0007] S2. Under an inert atmosphere, dissolve the aldehyde-containing aromatic halogenated hydrocarbon obtained in S1 in ethanol, heat and continuously stir, continue to add tertiary amine, react after heating, and perform rotary evaporation, then wash the product with n-hexane for 3 times, and dry it in a vacuum drying oven to obtain a double-headed hydrophilic precursor containing an aldehyde group;
[0008] S3. Dissolve the aldehyde-containing biaxial hydrophilic precursor and primary amine obtained in S2 in water and adjust the volume to a constant volume, and react at a constant temperature of 25° C. to obtain a Gemini surfactant.
[0009] Preferably, the molar ratio of potassium carbonate, 1,2-dibromoethane and p-hydroxybenzaldehyde in S1 is (1-3):(4-6):1.
[0010] Preferably, in S1, the heating temperature is 50-100° C., the heating time is 12-24 h, the vacuum drying temperature is 40-60° C., and the vacuum drying time is 12-24 h.
[0011] Preferably, the tertiary amine in S2 is one of tetramethylpropylenediamine, tetramethylbutylenediamine, tetramethylpentanediamine and tetramethylhexanediamine.
[0012] Preferably, the molar ratio of the aldehyde-containing aromatic halogenated hydrocarbon to the tertiary amine in S2 is (1-3):1.
[0013] Preferably, the heating temperature during heating and continuous stirring in S2 is 40-60°C, the heating temperature of the reaction after heating is 70-100°C, the heating time is 24-48h, the vacuum drying temperature is 40-60°C, and the vacuum drying time is 12-24h.
[0014] Preferably, the primary amine in S3 is one of octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine and hexadecylamine.
[0015] Preferably, the molar ratio of the aldehyde-containing double-headed hydrophilic precursor to the primary amine in S3 is 1:(1-3), and the isothermal reaction time is 12-24 hours.
[0016] Therefore, the present invention adopts the above-mentioned method for preparing a Gemini-type surfactant with pH responsiveness. The prepared Gemini-type surfactant has good pH responsiveness, can greatly enhance the surface tension of the liquid, and also has good emulsifying ability, and the demulsification behavior of the emulsion is controlled by regulating the pH.
[0017] The technical solution of the present invention is further described in detail below through embodiments. DETAILED DESCRIPTION
[0018] The technical solution of the present invention is further illustrated by the following examples.
[0019] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.
[0020] Example
[0021] The present invention provides a method for preparing a Gemini surfactant with pH responsiveness, comprising the following steps:
[0022] S1. Under an inert atmosphere, add potassium carbonate and 1,2-dibromoethane to a three-necked flask and dissolve them in acetonitrile. Heat and stir continuously. Dissolve p-hydroxybenzaldehyde in acetonitrile and slowly drip into the three-necked flask. Heat the mixed solution continuously at a temperature of 50-100°C for 12-24 hours. Filter after cooling to room temperature. Separate and purify the filtrate by column chromatography and then evaporate it by rotary evaporation. Dry it in a vacuum drying oven to obtain an aldehyde-containing aromatic halogenated hydrocarbon. The vacuum drying temperature is 40-60°C for 12-24 hours.
[0023] The chemical formula of aromatic halogenated hydrocarbons containing aldehyde groups is:
[0024]
[0025] The hydrogen spectrum is: 1 H NMR (400MHz, CDCl3) δ: 9.86-9.9 (m, 1H), 7.86-7.96 (m, 2H), 7.26 (d, J = 6.2Hz, 1H), 7.01-7.16 (m, 2H), 4.20-4.46 (m, 2H), 3.76-3.90 (m, 2H).
[0026] Wherein, the molar ratio of potassium carbonate, 1,2-dibromoethane and p-hydroxybenzaldehyde is (1-3):(4-6):1.
[0027] Potassium carbonate, as a weak base, can help promote the elimination of halogen atoms in halogenated hydrocarbon molecules. It can also act as a base to promote the reaction of halogenated aromatic hydrocarbons with carbon-containing nucleophiles, indirectly leading to the formation of aldehyde groups.
[0028] S2. Under an inert atmosphere, the aldehyde-containing aromatic halogenated hydrocarbon obtained in S1 is dissolved in acetonitrile, heated to 40-60°C and stirred continuously, and tertiary amine is continuously added, and the molar ratio of the aldehyde-containing aromatic halogenated hydrocarbon to the tertiary amine is (1-3):1. After heating to 70-100°C, the reaction is carried out for 24-48 hours, and rotary evaporation is performed, and then the product is washed with n-hexane for 3 times, and dried in a vacuum drying oven at 40-60°C for 12-24 hours to obtain a double-headed hydrophilic precursor containing an aldehyde group.
[0029] The tertiary amine is one of tetramethylpropylenediamine, tetramethylbutylenediamine, tetramethylpentanediamine and tetramethylhexanediamine. The tertiary amine and the halogenated hydrocarbon undergo nucleophilic substitution reaction to form a surfactant having a hydrophilic head and a hydrophobic tail. The alkylated product, as a surfactant, can accumulate on the interface, reduce the surface tension between water and other substances, and enhance the emulsification, dispersion, wetting and other properties.
[0030] The chemical formula of the double-headed hydrophilic precursor containing an aldehyde group is:
[0031]
[0032] The hydrogen spectrum is: 1 H NMR(400MHz,D2O)δ:9.83-9.93(m,2H),7.86-7.96(m,4H),6.98-7.16(m,4H),4.78-7.86(m,4H),4.69(d,J=6.2Hz 1H), 3.86-3.98(m,4H), 3.42-3.48(m,4H), 2.54-2.63(m,2H).
[0033] S3, dissolving the aldehyde-containing double-headed hydrophilic precursor and primary amine obtained in S2 in water and adjusting the volume, wherein the molar ratio of the aldehyde-containing double-headed hydrophilic precursor and the primary amine is 1:(1-3), and reacting at 25°C for 12-24 hours to obtain a Gemini surfactant. The primary amine is one of octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, and hexadecylamine, and the primary amine and the aldehyde group can generate an imine bond after Schiff base reaction, which is sensitive to pH, exists stably in an alkaline environment, and dissociates in an acidic environment.
[0034] The chemical formula of Gemini surfactant is:
[0035]
[0036] The hydrogen spectrum is: 1 H NMR(400MHz,D2O)δ:9.83-9.93(m,2H),7.86-7.96(m,4H),6.98-7.16(m,4H),4.78-7.86(m,4H), 4.69(d,J=6.2Hz,1H), 3.86-3.98(m,4H), 3.42-3.48(m,4H), 1.86-1.93(m,4H), 1.31-1.43(m,4H)
[0037] Example 1
[0038] The present invention provides a method for preparing a Gemini surfactant with pH responsiveness, comprising the following steps:
[0039] S1. In a N2 atmosphere, add 22.6g (0.16mol) potassium carbonate and 35.5mL (0.4mol) 1,2-dibromoethane to a 500mL three-necked flask and dissolve in 150mL acetonitrile, heat to 85°C and stir continuously. Weigh 10g (0.08mol) p-hydroxybenzaldehyde and dissolve in 100mL acetonitrile, then slowly drip into the three-necked flask. Heat the mixed solution at 85°C for 24h, cool to room temperature, filter to remove potassium carbonate, and use V 石油醚 :V 乙酸乙酯=5:1 as the developing solvent, the filtrate was separated and purified by column chromatography, then rotary evaporated, and dried in a vacuum drying oven at 50°C for 24h to obtain 12.3g of white crystals, which were 4-(2-bromoethoxy)benzaldehyde, with a yield of 65%.
[0040] S2. Under N2 atmosphere, add 10.1g (0.044mol) of 4-(2-bromoethoxy)benzaldehyde into a 500mL three-necked flask and dissolve it in 250mL of ethanol, heat to 50°C and stir continuously, continue to add 3.4g (0.02mol) of tetramethylhexanediamine, heat to 85°C and react for 48h, and obtain a crude product after rotary evaporation. Then wash the crude product with n-hexane 3 times, and dry it in a vacuum drying oven at 50°C for 24h to obtain 11.8g of white solid, which is a double-headed hydrophilic precursor containing an aldehyde group, with a yield of about 93%.
[0041] S3, take 0.63g (1mmol) of the double-headed hydrophilic precursor containing aldehyde group in S2 and 0.26g (2mmol) of octylamine, dissolve them in water and make up to 100mL volumetric flask, and react at 25℃ for 24h to obtain Gemini surfactant.
[0042] Example 2
[0043] The present invention provides a method for preparing a Gemini surfactant with pH responsiveness, comprising the following steps:
[0044] S1. In a N2 atmosphere, add 22.6g (0.16mol) potassium carbonate and 35.5mL (0.4mol) 1,2-dibromoethane to a 500mL three-necked flask and dissolve in 150mL acetonitrile, heat to 85°C and stir continuously. Weigh 10g (0.08mol) p-hydroxybenzaldehyde and dissolve in 100mL acetonitrile, then slowly drip into the three-necked flask. Heat the mixed solution at 85°C for 24h, cool to room temperature, filter to remove potassium carbonate, and use V 石油醚 :V 乙酸乙酯 =5:1 as the developing solvent, the filtrate was separated and purified by column chromatography, then rotary evaporated, and dried in a vacuum drying oven at 50°C for 24h to obtain 12.3g of white crystals, which were 4-(2-bromoethoxy)benzaldehyde, with a yield of 65%.
[0045] S2. Under N2 atmosphere, add 10.1g (0.044mol) of 4-(2-bromoethoxy)benzaldehyde into a 500mL three-necked flask and dissolve it in 250mL of ethanol, heat to 50°C and stir continuously, continue to add 3.4g (0.02mol) of tetramethylhexanediamine, heat to 85°C and react for 48h, and obtain a crude product after rotary evaporation. Then wash the crude product with n-hexane 3 times, and dry it in a vacuum drying oven at 50°C for 24h to obtain 11.8g of white solid, which is a double-headed hydrophilic precursor containing an aldehyde group, with a yield of about 93%.
[0046] S3, take 0.63g (1mmol) of the double-headed hydrophilic precursor containing aldehyde group in S2 and 0.32g (2mmol) of decylamine, dissolve them in water and make up to 100mL volumetric flask, and react at 25℃ for 24h to obtain Gemini surfactant.
[0047] Example 3
[0048] The present invention provides a method for preparing a Gemini surfactant with pH responsiveness, comprising the following steps:
[0049] S1. In a N2 atmosphere, add 22.6g (0.16mol) potassium carbonate and 35.5mL (0.4mol) 1,2-dibromoethane to a 500mL three-necked flask and dissolve in 150mL acetonitrile, heat to 85°C and stir continuously. Weigh 10g (0.08mol) p-hydroxybenzaldehyde and dissolve in 100mL acetonitrile, then slowly drip into the three-necked flask. Heat the mixed solution at 85°C for 24h, cool to room temperature, filter to remove potassium carbonate, and use V 石油醚 :V 乙酸乙酯 =5:1 as the developing solvent, the filtrate was separated and purified by column chromatography, then rotary evaporated, and dried in a vacuum drying oven at 50°C for 24h to obtain 12.3g of white crystals, which were 4-(2-bromoethoxy)benzaldehyde, with a yield of 65%.
[0050] S2. Under N2 atmosphere, add 10.1g (0.044mol) of 4-(2-bromoethoxy)benzaldehyde into a 500mL three-necked flask and dissolve it in 250mL of ethanol, heat to 50°C and stir continuously, continue to add 3.4g (0.02mol) of tetramethylhexanediamine, heat to 85°C and react for 48h, and obtain a crude product after rotary evaporation. Then wash the crude product with n-hexane 3 times, and dry it in a vacuum drying oven at 50°C for 24h to obtain 11.8g of white solid, which is a double-headed hydrophilic precursor containing an aldehyde group, with a yield of about 93%.
[0051] S3, take 0.63g (1mmol) of the double-headed hydrophilic precursor containing aldehyde group in S2 and 0.37g (2mmol) of dodecylamine, dissolve them in water and make up to 100mL volumetric flask, and react at 25℃ for 24h to obtain Gemini surfactant.
[0052] Example 4
[0053] The present invention provides a method for preparing a Gemini surfactant with pH responsiveness, comprising the following steps:
[0054] S1. In a N2 atmosphere, add 22.6g (0.16mol) potassium carbonate and 35.5mL (0.4mol) 1,2-dibromoethane to a 500mL three-necked flask and dissolve in 150mL acetonitrile, heat to 85°C and stir continuously. Weigh 10g (0.08mol) p-hydroxybenzaldehyde and dissolve in 100mL acetonitrile, then slowly drip into the three-necked flask. Heat the mixed solution at 85°C for 24h, cool to room temperature, filter to remove potassium carbonate, and use V 石油醚 :V 乙酸乙酯 =5:1 as the developing solvent, the filtrate was separated and purified by column chromatography, then rotary evaporated, and dried in a vacuum drying oven at 50°C for 24h to obtain 12.3g of white crystals, which were 4-(2-bromoethoxy)benzaldehyde, with a yield of 65%.
[0055] S2. Under N2 atmosphere, add 10.1g (0.044mol) of 4-(2-bromoethoxy)benzaldehyde into a 500mL three-necked flask and dissolve it in 250mL of ethanol, heat to 50°C and stir continuously, continue to add 3.4g (0.02mol) of tetramethylhexanediamine, heat to 85°C and react for 48h, and obtain a crude product after rotary evaporation. Then wash the crude product with n-hexane 3 times, and dry it in a vacuum drying oven at 50°C for 24h to obtain 11.8g of white solid, which is a double-headed hydrophilic precursor containing an aldehyde group, with a yield of about 93%.
[0056] S3, take 0.63g (1mmol) of the double-headed hydrophilic precursor containing aldehyde group in S2 and 0.43g (2mmol) of tetradecylamine, dissolve them in water and make up to 100mL volumetric flask, and react at 25℃ for 24h to obtain Gemini surfactant.
[0057] Example 5
[0058] The present invention provides a method for preparing a Gemini surfactant with pH responsiveness, comprising the following steps:
[0059] S1. In a N2 atmosphere, add 22.6g (0.16mol) potassium carbonate and 35.5mL (0.4mol) 1,2-dibromoethane to a 500mL three-necked flask and dissolve in 150mL acetonitrile, heat to 85°C and stir continuously. Weigh 10g (0.08mol) p-hydroxybenzaldehyde and dissolve in 100mL acetonitrile, then slowly drip into the three-necked flask. Heat the mixed solution at 85°C for 24h, cool to room temperature, filter to remove potassium carbonate, and use V 石油醚 :V 乙酸乙酯 =5:1 as the developing solvent, the filtrate was separated and purified by column chromatography, then rotary evaporated, and dried in a vacuum drying oven at 50°C for 24h to obtain 12.3g of white crystals, which were 4-(2-bromoethoxy)benzaldehyde, with a yield of 65%.
[0060] S2. Under N2 atmosphere, add 10.1g (0.044mol) of 4-(2-bromoethoxy)benzaldehyde into a 500mL three-necked flask and dissolve it in 250mL of ethanol, heat to 50°C and stir continuously, continue to add 3.4g (0.02mol) of tetramethylhexanediamine, heat to 85°C and react for 48h, and obtain a crude product after rotary evaporation. Then wash the crude product with n-hexane 3 times, and dry it in a vacuum drying oven at 50°C for 24h to obtain 11.8g of white solid, which is a double-headed hydrophilic precursor containing an aldehyde group, with a yield of about 93%.
[0061] S3, take 0.63g (1mmol) of the double-headed hydrophilic precursor containing aldehyde group in S2 and 0.48g (2mmol) of hexadecylamine, dissolve them in water and make up to 100mL volumetric flask, and react at 25℃ for 24h to obtain Gemini surfactant.
[0062] Example 6
[0063] The present invention provides a method for preparing a Gemini surfactant with pH responsiveness, comprising the following steps:
[0064] S1. In a N2 atmosphere, add 22.6g (0.16mol) potassium carbonate and 35.5mL (0.4mol) 1,2-dibromoethane to a 500mL three-necked flask and dissolve in 150mL acetonitrile, heat to 85°C and stir continuously. Weigh 10g (0.08mol) p-hydroxybenzaldehyde and dissolve in 100mL acetonitrile, then slowly drip into the three-necked flask. Heat the mixed solution at 85°C for 24h, cool to room temperature, filter to remove potassium carbonate, and use V 石油醚 :V 乙酸乙酯=5:1 as the developing solvent, the filtrate was separated and purified by column chromatography, then rotary evaporated, and dried in a vacuum drying oven at 50°C for 24h to obtain 12.3g of white crystals, which were 4-(2-bromoethoxy)benzaldehyde, with a yield of 65%.
[0065] S2. Under N2 atmosphere, add 10.1g (0.044mol) of 4-(2-bromoethoxy)benzaldehyde into a 500mL three-necked flask and dissolve it in 250mL of ethanol, heat to 50°C and stir continuously, continue to add 2.6g (0.02mol) of tetramethylpropylenediamine, heat to 85°C and react for 48h, and obtain a crude product after rotary evaporation. Subsequently, the crude product is washed 3 times with n-hexane and dried in a vacuum drying oven at 50°C for 24h to obtain 6.6g of white solid, which is a double-headed hydrophilic precursor containing an aldehyde group, with a yield of about 56%.
[0066] S3, take 0.58g (1mmol) of the double-headed hydrophilic precursor containing aldehyde group in S2 and 0.26g (2mmol) of tetradecylamine, dissolve them in water and make up to 100mL volumetric flask, and react at 25℃ for 24h to obtain Gemini surfactant.
[0067] Example 7
[0068] The present invention provides a method for preparing a Gemini surfactant with pH responsiveness, comprising the following steps:
[0069] S1. In a N2 atmosphere, add 22.6g (0.16mol) potassium carbonate and 35.5mL (0.4mol) 1,2-dibromoethane to a 500mL three-necked flask and dissolve in 150mL acetonitrile, heat to 85°C and stir continuously. Weigh 10g (0.08mol) p-hydroxybenzaldehyde and dissolve in 100mL acetonitrile, then slowly drip into the three-necked flask. Heat the mixed solution at 85°C for 24h, cool to room temperature, filter to remove potassium carbonate, and use V 石油醚 :V 乙酸乙酯 =5:1 as the developing solvent, the filtrate was separated and purified by column chromatography, then rotary evaporated, and dried in a vacuum drying oven at 50°C for 24h to obtain 12.3g of white crystals, which were 4-(2-bromoethoxy)benzaldehyde, with a yield of 65%.
[0070] S2. Under N2 atmosphere, add 10.1g (0.044mol) of 4-(2-bromoethoxy)benzaldehyde into a 500mL three-necked flask and dissolve it in 250mL of ethanol, heat to 50°C and stir continuously, continue to add 2.6g (0.02mol) of tetramethylpropylenediamine, heat to 85°C and react for 48h, and obtain a crude product after rotary evaporation. Subsequently, the crude product is washed 3 times with n-hexane and dried in a vacuum drying oven at 50°C for 24h to obtain 6.6g of white solid, which is a double-headed hydrophilic precursor containing an aldehyde group, with a yield of about 56%.
[0071] S3, take 0.58g (1mmol) of the double-headed hydrophilic precursor containing aldehyde group in S2 and 0.32g (2mmol) of decylamine, dissolve them in water and make up to 100mL volumetric flask, and react at 25℃ for 24h to obtain Gemini surfactant.
[0072] Example 8
[0073] The present invention provides a method for preparing a Gemini surfactant with pH responsiveness, comprising the following steps:
[0074] S1. In a N2 atmosphere, add 22.6g (0.16mol) potassium carbonate and 35.5mL (0.4mol) 1,2-dibromoethane to a 500mL three-necked flask and dissolve in 150mL acetonitrile, heat to 85°C and stir continuously. Weigh 10g (0.08mol) p-hydroxybenzaldehyde and dissolve in 100mL acetonitrile, then slowly drip into the three-necked flask. Heat the mixed solution at 85°C for 24h, cool to room temperature, filter to remove potassium carbonate, and use V 石油醚 :V 乙酸乙酯 =5:1 as the developing solvent, the filtrate was separated and purified by column chromatography, then rotary evaporated, and dried in a vacuum drying oven at 50°C for 24h to obtain 12.3g of white crystals, which were 4-(2-bromoethoxy)benzaldehyde, with a yield of 65%.
[0075] S2. Under N2 atmosphere, add 10.1g (0.044mol) of 4-(2-bromoethoxy)benzaldehyde into a 500mL three-necked flask and dissolve it in 250mL of ethanol, heat to 50°C and stir continuously, continue to add 2.6g (0.02mol) of tetramethylpropylenediamine, heat to 85°C and react for 48h, and obtain a crude product after rotary evaporation. Subsequently, the crude product is washed 3 times with n-hexane and dried in a vacuum drying oven at 50°C for 24h to obtain 6.6g of white solid, which is a double-headed hydrophilic precursor containing an aldehyde group, with a yield of about 56%.
[0076] S3, take 0.58g (1mmol) of the double-headed hydrophilic precursor containing aldehyde group in S2 and 0.37g (2mmol) of dodecylamine, dissolve them in water and make up to 100mL volumetric flask, and react at 25℃ for 24h to obtain Gemini surfactant.
[0077] Example 9
[0078] The present invention provides a method for preparing a Gemini surfactant with pH responsiveness, comprising the following steps:
[0079] S1. In a N2 atmosphere, add 22.6g (0.16mol) potassium carbonate and 35.5mL (0.4mol) 1,2-dibromoethane to a 500mL three-necked flask and dissolve in 150mL acetonitrile, heat to 85°C and stir continuously. Weigh 10g (0.08mol) p-hydroxybenzaldehyde and dissolve in 100mL acetonitrile, then slowly drip into the three-necked flask. Heat the mixed solution at 85°C for 24h, cool to room temperature, filter to remove potassium carbonate, and use V 石油醚 :V 乙酸乙酯 =5:1 as the developing solvent, the filtrate was separated and purified by column chromatography, then rotary evaporated, and dried in a vacuum drying oven at 50°C for 24h to obtain 12.3g of white crystals, which were 4-(2-bromoethoxy)benzaldehyde, with a yield of 65%.
[0080] S2. Under N2 atmosphere, add 10.1g (0.044mol) of 4-(2-bromoethoxy)benzaldehyde into a 500mL three-necked flask and dissolve it in 250mL of ethanol, heat to 50°C and stir continuously, continue to add 2.6g (0.02mol) of tetramethylpropylenediamine, heat to 85°C and react for 48h, and obtain a crude product after rotary evaporation. Subsequently, the crude product is washed 3 times with n-hexane and dried in a vacuum drying oven at 50°C for 24h to obtain 6.6g of white solid, which is a double-headed hydrophilic precursor containing an aldehyde group, with a yield of about 56%.
[0081] S3, take 0.58g (1mmol) of the double-headed hydrophilic precursor containing aldehyde group in S2 and 0.43g (2mmol) of tetradecylamine, dissolve them in water and make up to 100mL volumetric flask, and react at 25℃ for 24h to obtain Gemini surfactant.
[0082] Example 10
[0083] The present invention provides a method for preparing a Gemini surfactant with pH responsiveness, comprising the following steps:
[0084] S1. In a N2 atmosphere, add 22.6g (0.16mol) potassium carbonate and 35.5mL (0.4mol) 1,2-dibromoethane to a 500mL three-necked flask and dissolve in 150mL acetonitrile, heat to 85°C and stir continuously. Weigh 10g (0.08mol) p-hydroxybenzaldehyde and dissolve in 100mL acetonitrile, then slowly drip into the three-necked flask. Heat the mixed solution at 85°C for 24h, cool to room temperature, filter to remove potassium carbonate, and use V 石油醚 :V 乙酸乙酯 =5:1 as the developing solvent, the filtrate was separated and purified by column chromatography, then rotary evaporated, and dried in a vacuum drying oven at 50°C for 24h to obtain 12.3g of white crystals, which were 4-(2-bromoethoxy)benzaldehyde, with a yield of 65%.
[0085] S2. Under N2 atmosphere, add 10.1g (0.044mol) of 4-(2-bromoethoxy)benzaldehyde into a 500mL three-necked flask and dissolve it in 250mL of ethanol, heat to 50°C and stir continuously, continue to add 2.6g (0.02mol) of tetramethylpropylenediamine, heat to 85°C and react for 48h, and obtain a crude product after rotary evaporation. Subsequently, the crude product is washed 3 times with n-hexane and dried in a vacuum drying oven at 50°C for 24h to obtain 6.6g of white solid, which is a double-headed hydrophilic precursor containing an aldehyde group, with a yield of about 56%.
[0086] S3. Take 0.58 g (1 mmol) of the double-headed hydrophilic precursor containing aldehyde groups in S2 and 0.48 g (2 mmol) of hexadecylamine, dissolve them in water and make up to 100 mL volumetric flask, and react at a constant temperature of 25°C for 24 hours to obtain the Gemini surfactant.
[0087] Therefore, the present invention adopts the above-mentioned method for preparing a Gemini-type surfactant with pH responsiveness. The prepared Gemini-type surfactant has good pH responsiveness, can greatly enhance the surface tension of the liquid, and also has good emulsifying ability, and the demulsification behavior of the emulsion is controlled by regulating the pH.
[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.
Claims
1. A method for preparing a Gemini surfactant with pH responsiveness, characterized in that: The following steps are involved: S1. Under an inert atmosphere, potassium carbonate and 1,2-dibromoethane are added to a three-necked flask and dissolved in ethanol. The mixture is heated and stirred continuously. p-hydroxybenzaldehyde is dissolved in acetonitrile and then slowly dripped into the three-necked flask. The mixed solution is continuously heated, cooled to room temperature and filtered. The filtrate is separated and purified by column chromatography, and then rotary evaporated and dried in a vacuum drying oven to obtain an aldehyde-containing aromatic halogenated hydrocarbon. S2. Under an inert atmosphere, dissolve the aldehyde-containing aromatic halogenated hydrocarbon obtained in S1 in acetonitrile, heat and continuously stir, continue to add tertiary amine, react after heating, and perform rotary evaporation, then wash the product with n-hexane for 3 times, and dry it in a vacuum drying oven to obtain a double-headed hydrophilic precursor containing an aldehyde group; S3. Dissolve the aldehyde-containing biaxial hydrophilic precursor and primary amine obtained in S2 in water and adjust the volume to a constant volume, and react at a constant temperature of 25° C. to obtain a Gemini surfactant.
2. The method for preparing a pH-responsive Gemini surfactant according to claim 1, characterized in that: The molar ratio of potassium carbonate, 1,2-dibromoethane and p-hydroxybenzaldehyde in S1 is (1-3):(4-6):
1.
3. The method for preparing a pH-responsive Gemini surfactant according to claim 1, characterized in that: In S1, the heating temperature is 50-100° C., the heating time is 12-24 hours, the vacuum drying temperature is 40-60° C., and the vacuum drying time is 12-24 hours.
4. The method for preparing a pH-responsive Gemini surfactant according to claim 1, characterized in that: The tertiary amine in S2 is one of tetramethylpropylenediamine, tetramethylbutylenediamine, tetramethylpentanediamine and tetramethylhexanediamine.
5. The method for preparing a pH-responsive Gemini surfactant according to claim 1, characterized in that: The molar ratio of the aldehyde-containing aromatic halogenated hydrocarbon to the tertiary amine in S2 is (1-3):
1.
6. The method for preparing a pH-responsive Gemini surfactant according to claim 1, characterized in that: The heating temperature during heating and continuous stirring in S2 is 40-60°C, the heating temperature of the reaction after heating is 70-100°C, the heating time is 24-48h, the vacuum drying temperature is 40-60°C, and the vacuum drying time is 12-24h.
7. The method for preparing a pH-responsive Gemini surfactant according to claim 1, characterized in that: The primary amine in S3 is one of octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine and hexadecylamine.
8. The method for preparing a pH-responsive Gemini surfactant according to claim 1, characterized in that: The molar ratio of the aldehyde-containing double-headed hydrophilic precursor to the primary amine in S3 is 1:(1-3), and the isothermal reaction time is 12-24 hours.