Background
The surfactant is an amphiphilic compound containing a nonpolar oleophilic group and a polar hydrophilic group in a molecular structure, can form directional arrangement on a gas-liquid interface and a solid-liquid interface, can remarkably reduce the surface tension of the solution by adding a small amount of the surfactant into the solution, and effectively changes the physical and chemical properties of the interface. Therefore, the method is widely applied to the fields of daily life, industry and agriculture, high and new technology and the like, and becomes one of important industries of chemical processes. The surfactant industry has the defects of single variety, simple structure, lagged process and the like due to the long-standing weak foundation, and particularly, the high-end surfactant product and technology have great gap with foreign countries.
Disclosure of Invention
In order to enrich the types of surfactants and endow the surfactants with functionalization, the invention designs and prepares a double-carboxyl surfactant with cation and anion reversal capability and a preparation method thereof.
In order to achieve the purpose, the invention adopts the following technical scheme:
a bi-carboxyl surfactant with anion-cation reversal capability, the structural formula of the compound is as follows:
as a further improvement of the invention, the surfactant reverses the properties of cations and anions according to the change of the pH value of the external environment.
As a further improvement of the invention, the bi-carboxyl surfactant is an anionic surfactant under the condition that the external environment is alkaline, and is a cationic surfactant under the condition that the external environment is acidic. The surfactant has excellent anion-cation reversal characteristics, and the type of the surfactant can be changed according to the external environment. The anionic surfactant is used under the condition that the external environment is alkaline, and the cationic surfactant is used under the condition that the external environment is acidic.
A method for preparing a dicarboxyl surfactant with cation and anion reversal capability comprises the following steps:
mixing dodecylamine and cyclobut-3-ene dicarboxylic anhydride, introducing nitrogen, and performing nucleophilic addition-elimination reaction at 150-200 ℃ to generate imide;
adding reducing agent LiAlH into imide4Reducing carbonyl at 0-35 ℃;
and adding an oxidant potassium permanganate, heating to 90-100 ℃ for oxidation reaction to generate carboxyl, and performing post-treatment to obtain a final product.
As a further improvement of the present invention, the nucleophilic addition-elimination reaction is carried out in a molar ratio of dodecylamine to cyclobut-3-enedicarboxylic anhydride of 1: 2.
As a further improvement of the invention, in the reduced carbonyl group, LiAlH4The mol ratio of the dodecylamine to the dodecylamine is 1-1.2: 1;
as a further improvement of the invention, the amount of the potassium permanganate substance is 1-2 times of the amount of the dodecylamine substance.
As a further improvement of the invention, in the oxidation reaction, after the product after carbonyl reduction is diluted, potassium permanganate is slowly added at 0 ℃, and then the temperature is raised for reaction.
As a further development of the invention, the post-treatment comprises:
and after the reaction is finished, adding sodium sulfite to remove excessive potassium permanganate, filtering by adopting diatomite and extracting impurities by adopting ethyl acetate, collecting a water phase, adjusting the pH value to be 2-4 to separate out a product, and filtering and drying to constant weight to obtain a final product.
The invention has the following advantages:
the preparation method generates imide through the nucleophilic addition-elimination reaction of dodecylamine and cyclobut-3-ene dicarboxylic anhydride, and uses LiAlH4Reducing the imide to a reducing agent; and then a final product is obtained by a reducing agent potassium permanganate. The whole preparation method is simple and convenient, and the dicarboxyl surfactant with the anion-cation reversal capability is prepared.
The prepared double-carboxyl surfactant with negative and positive ion reversal capability can be applied to the fields of oil exploitation, crude oil recovery, soil remediation and the like. The surfactant has excellent anion-cation reversal characteristics, and the type of the surfactant can be changed according to the external environment. The anionic surfactant is used under the condition that the external environment is alkaline, and the cationic surfactant is used under the condition that the external environment is acidic.
Detailed Description
The invention relates to a bi-carboxyl surfactant with anion-cation reversal capability, the reaction equation of the preparation process is as follows:
according to the reaction mechanism, the invention adopts the following technical scheme:
a bi-carboxyl surfactant with anion-cation reversal capability has a structural formula as follows:
the method for preparing the double-carboxyl surfactant with the anion-cation reversal capability comprises the following steps:
1) dripping dodecylamine and cyclobut-3-ene dicarboxylic anhydride into a three-neck flask provided with a reflux condenser tube in sequence, introducing nitrogen, reacting for 2-5 h at 150-200 ℃, and performing a first nucleophilic addition-elimination reaction to generate imide, wherein the molar ratio of the dodecylamine to the cyclobut-3-ene dicarboxylic anhydride is 1: 2; followed by LiAlH4Reduction of imide for reducing agent, in which LiAlH4The mol ratio of the catalyst to the dodecylamine is 1-1.2: 1, the reduction temperature is 0-35 ℃, and the optimization is 20 DEG CThe reduction time is 4-6 h at the temperature of-35 ℃.
2) Diluting the product, slowly adding potassium permanganate at 0 ℃, and heating to react for 10-12 h, wherein the amount of potassium permanganate is 1-2 times of that of dodecylamine; and reducing excessive potassium permanganate by using sodium sulfite, dropwise adding dilute hydrochloric acid until the pH of the reaction solution is 2-4, separating out the product, and filtering and drying to constant weight to obtain the final product.
The surfactant can realize reversal of anion and cation properties according to the change of external environment pH.
The inversion principle of the bi-carboxyl surfactant with the anion-cation inversion capability is realized by the following reactions:
the bi-carboxyl surfactant with the anion-cation reversal capability is an anionic surfactant under the condition that the external environment is alkaline, and is a cationic surfactant under the condition that the external environment is acidic.
The technical solution in the embodiments of the present invention will be clearly and completely described below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
(1) In a 250mL three-necked flask equipped with a reflux condenser, dodecylamine (18.5g, 0.1mol) and cyclobutane-3-enedicarboxylic anhydride (24.8g, 0.2mol) were added dropwise in this order, and nitrogen was introduced 3 times, followed by heating to 180 ℃ for 3 hours, and TLC (Thin Layer Chromatography) was used to monitor completion of the reaction. After the reaction is finished, cooling to room temperature, adding 50mL of distilled water, extracting for 3 times by adopting 80mL of ethyl acetate, drying by anhydrous magnesium sulfate, filtering, concentrating under reduced pressure to obtain a crude product, and finally separating by a column to obtain colorless oily imide.
(2) 80mL of tetrahydrofuran dried over sodium metal were added to 250mL of trisIn a flask, the mixture was cooled to 0 ℃ using a cold salt bath, and 3.8g of LiAlH was slowly added in portions4After stirring for 3min, slowly dropwise adding the imide dissolved in tetrahydrofuran into a three-neck flask, and raising the temperature to 25 ℃ after the addition is finished to react for 4 h. The completion of the reaction was monitored by TLC (thinLayerChromatography). After the reaction is finished, cooling to 0 ℃, and sequentially adding 3.8mLH into the mixture under ice salt bath2O, 3.8mL 15% aqueous NaOH and 11.4mLH2O quenching excess LiAlH4Filtering, fully washing a filter cake by using 20ml of ethyl acetate, drying the filtrate by using anhydrous magnesium sulfate, concentrating under reduced pressure to obtain a crude product, and finally separating by using a column to obtain the product.
(3) Adding the product and 40mL of distilled water into a 250mL three-neck flask, placing the three-neck flask in an ice salt bath, cooling to 0 ℃, and slowly adding potassium permanganate KMnO4(20g, the adding time is 40min), and after the adding is finished, slowly raising the temperature to 90 ℃ for reaction for 12 h. Excess KMnO was quenched by adding 80mL of saturated aqueous sodium sulfite solution to a three-necked flask4(ii) a After the purple color is faded, slowly cooling and filtering MnO generated in the reaction by diatomite while the MnO is hot2Obtaining clear filtrate; then extracting the filtrate for 3 times by using ethyl acetate to remove impurities, collecting a water phase, adjusting the pH value of the water phase to 2 by using dilute hydrochloric acid to precipitate a solid, and filtering and drying to obtain a pure final product.
The product obtained in example 1 was obtained in 58% yield.
Example 2
(1) In a 250mL three-necked flask equipped with a reflux condenser, dodecylamine (18.5g, 0.1mol) and cyclobutane-3-enedicarboxylic anhydride (24.8g, 0.2mol) were added dropwise in this order, and nitrogen was introduced 3 times, followed by heating to 150 ℃ for 2 hours, and completion of the reaction was monitored by TLC (Thin Layer Chromatography). After the reaction is finished, cooling to room temperature, adding 50mL of distilled water, extracting for 3 times by adopting 80mL of ethyl acetate, drying by anhydrous magnesium sulfate, filtering, concentrating under reduced pressure to obtain a crude product, and finally separating by a column to obtain colorless oily imide.
(2) 90mL of tetrahydrofuran dried with sodium metal were charged into a 250mL three-necked flask, cooled to 0 ℃ using a cold salt bath, and 4.18g of LiAlH were slowly added in portions4Stirring for 3min, dissolving in tetrahydrofuranThe imide in the pyran is slowly dripped into a three-neck flask, and after the addition is finished, the temperature is raised to 30 ℃ for reaction for 5 hours. The completion of the reaction was monitored by TLC (thinLayerChromatography). After the reaction is finished, cooling to 0 ℃, and sequentially adding 4.2mLH under ice salt bath2O, 4.2mL 15% aqueous NaOH solution and 12.6mLH2O quenching excess LiAlH4Filtering, fully washing a filter cake by using 20ml of ethyl acetate, drying the filtrate by using anhydrous magnesium sulfate, concentrating under reduced pressure to obtain a crude product, and finally separating by using a column to obtain the product.
(3) Adding the product and 40mL of distilled water into a 250mL three-neck flask, placing the three-neck flask in an ice salt bath, cooling to 0 ℃, and slowly adding potassium permanganate KMnO4(15.8g, the adding time is 40min), after the adding is finished, the temperature is slowly raised to 100 ℃ for reaction for 10 h. Excess KMnO was quenched by adding 80mL of saturated aqueous sodium sulfite solution to a three-necked flask4(ii) a After the purple color is faded, slowly cooling and filtering MnO generated in the reaction by diatomite while the MnO is hot2Obtaining clear filtrate; then extracting the filtrate for 3 times by using ethyl acetate to remove impurities, collecting a water phase, adjusting the pH value of the water phase to 3 by using dilute hydrochloric acid to precipitate a solid, and filtering and drying to obtain a pure final product.
The yield of the product obtained in example 2 was 51%.
Example 3
(1) In a 250mL three-necked flask equipped with a reflux condenser, dodecylamine (18.5g, 0.1mol) and cyclobutane-3-enedicarboxylic anhydride (24.8g, 0.2mol) were added dropwise in this order, and nitrogen was introduced 3 times, followed by heating to 200 ℃ for 5 hours, and completion of the reaction was monitored by TLC (Thin Layer Chromatography). After the reaction is finished, cooling to room temperature, adding 50mL of distilled water, extracting for 3 times by adopting 80mL of ethyl acetate, drying by anhydrous magnesium sulfate, filtering, concentrating under reduced pressure to obtain a crude product, and finally separating by a column to obtain colorless oily imide.
(2) 100mL of tetrahydrofuran dried with sodium metal was charged into a 250mL three-necked flask, cooled to 0 ℃ using a cold salt bath, and 3.99g of LiAlH was slowly added in portions4After stirring for 3min, slowly dropwise adding the imide dissolved in tetrahydrofuran into a three-neck flask, and raising the temperature to 35 ℃ after the addition for reacting for 6 h. TLC (thinLayerChromatograpy, thin layer)Chromatography) to monitor the reaction for completion. Cooling to 0 deg.C after reaction, adding 4mLH in sequence under ice salt bath2O, 4mL of 15% aqueous NaOH solution and 12mLH2O quenching excess LiAlH4Filtering, fully washing a filter cake by using 20ml of ethyl acetate, drying the filtrate by using anhydrous magnesium sulfate, concentrating under reduced pressure to obtain a crude product, and finally separating by using a column to obtain the product.
(3) Adding the product and 40mL of distilled water into a 250mL three-neck flask, placing the three-neck flask in an ice salt bath, cooling to 0 ℃, and slowly adding potassium permanganate KMnO4(25g, the addition time is 40min), and after the addition is finished, the temperature is slowly raised to 90 ℃ for reaction for 12 h. Excess KMnO was quenched by adding 80mL of saturated aqueous sodium sulfite solution to a three-necked flask4(ii) a After the purple color is faded, slowly cooling and filtering MnO generated in the reaction by diatomite while the MnO is hot2Obtaining clear filtrate; then extracting the filtrate for 3 times by using ethyl acetate to remove impurities, collecting a water phase, adjusting the pH value of the water phase to 4 by using dilute hydrochloric acid to precipitate solids, and filtering and drying to obtain a pure final product.
The product obtained in example 3 was obtained in 53% yield.
Example 4
(1) In a 250mL three-necked flask equipped with a reflux condenser, dodecylamine (18.5g, 0.1mol) and cyclobutane-3-enedicarboxylic anhydride (24.8g, 0.2mol) were added dropwise in this order, and nitrogen was introduced 3 times, followed by heating to 190 ℃ for 5 hours, and completion of the reaction was monitored by TLC (Thin Layer Chromatography). After the reaction is finished, cooling to room temperature, adding 50mL of distilled water, extracting for 3 times by adopting 80mL of ethyl acetate, drying by anhydrous magnesium sulfate, filtering, concentrating under reduced pressure to obtain a crude product, and finally separating by a column to obtain colorless oily imide.
(2) 80mL of tetrahydrofuran dried with sodium metal were charged into a 250mL three-necked flask, cooled to 0 ℃ using a cold salt bath, and 4.56g of LiAlH were slowly added in portions4After stirring for 3min, slowly dropwise adding the imide dissolved in tetrahydrofuran into a three-neck flask, and raising the temperature to 20 ℃ after the addition is finished to react for 6 h. The completion of the reaction was monitored by TLC (thinLayerChromatography). After the reaction is finished, cooling to 0 ℃, and sequentially adding 4.6mLH under ice salt bath2O, 4.6mL 15% NaOH in waterLiquid and 13.8mLH2O quenching excess LiAlH4Filtering, fully washing a filter cake by using 20ml of ethyl acetate, drying the filtrate by using anhydrous magnesium sulfate, concentrating under reduced pressure to obtain a crude product, and finally separating by using a column to obtain the product.
(3) Adding the product and 40mL of distilled water into a 250mL three-neck flask, placing the three-neck flask in an ice salt bath, cooling to 0 ℃, and slowly adding potassium permanganate KMnO4(31.6g, the addition time is 40min), and after the addition is finished, the temperature is slowly raised to 100 ℃ for reaction for 10 h. Excess KMnO was quenched by adding 80mL of saturated aqueous sodium sulfite solution to a three-necked flask4(ii) a After the purple color is faded, slowly cooling and filtering MnO generated in the reaction by diatomite while the MnO is hot2Obtaining clear filtrate; then extracting the filtrate for 3 times by using ethyl acetate to remove impurities, collecting a water phase, adjusting the pH value of the water phase to 2 by using dilute hydrochloric acid to precipitate a solid, and filtering and drying to obtain a pure final product.
The product obtained in example 4 was obtained in 60% yield.
In order to characterize the structural characteristics of a dicarboxyl surfactant with cation and anion reversal capability, the dicarboxyl surfactant with cation and anion reversal capability synthesized in example 4 was subjected to nuclear magnetic hydrogen spectroscopy, and the results are shown as follows:
1H NMR(300MHz,DMSO):12.13(s,2H),2.78-2.43(m,8H),1.36-1.26(m,20H),0.88(t,J=7.4Hz,3H)ppm。
in order to characterize the surface tension of a dicarboxyl surfactant with the ability to reverse the cations and anions. The surfactant solution of example 4 was tested for surface tension using a JK99C full automatic surface tensiometer. First, a surfactant solution having a concentration of 0.01mol/L was prepared, and the surface tension thereof was measured at 25 ℃. Continuously reading 5 data with rise and fall in the testing process, wherein the difference of the 5 data is less than 1, taking the average value of the data as the final surface tension value of the solution, and the testing method is a platinum ring method. The surface tension of the surfactant solution as a function of pH is shown in figure 2. As can be seen, as the pH of the surfactant solution increases, its surface tension increases first and then decreases. When the pH is 6, the surface tension reaches a maximum of 65.2mN/m, indicating that the surfactant has a strong surface activity under acidic or alkaline conditions.
The foregoing is a more detailed description of the invention and it is not intended that the invention be limited to the specific embodiments described herein, but that various modifications, alterations, and substitutions may be made by those skilled in the art without departing from the spirit of the invention, which should be construed to fall within the scope of the invention as defined by the appended claims.