Preparation method of cashew phenol-based ionic liquid surfactant

Abstract

The application discloses a preparation method of a cardanol-based ionic liquid surfactant, and specifically implements the following steps: step 1, raw materials of cardanol, glycine and paraformaldehyde are configured into a mixture, oil bath heating is performed to obtain a layered solution, the upper liquid of the layered solution is removed, and the lower product is dried to obtain a benzoxazine structure intermediate product; step 2, a choline hydroxide solution is added drop by drop into the benzoxazine structure intermediate product, and methanol is added as a solvent to obtain a dissolution reaction product, the solvent in the dissolution reaction product is removed, a light yellow viscous liquid at room temperature is obtained, and after drying, the cardanol-based ionic liquid surfactant is obtained. The application solves the problems of the prior art, such as that raw materials of the ionic liquid surfactant are mostly petrochemical materials, the use cost is high, the synthesis process is complex, and a large amount of toxic organic solvents are needed.

Description

Technical Field

[0001] The invention belongs to the technical field of surfactants and relates to a method for preparing a cardanol-based ionic liquid surfactant. Background Art

[0002] In recent years, with growing environmental awareness, the use of non-toxic, green solvents to replace organic solvents has gradually gained attention. Various green solvents, such as water, supercritical fluids, and ionic liquids, have garnered widespread attention. Ionic liquids, a new type of green solvent, are molten salts composed entirely of organic or inorganic ions. Due to their advantages such as low volatility, good thermal stability, and strong structural designability, they are known as "designable green solvents" and have experienced rapid development in recent decades. There are many types of ionic liquids, which can be simply classified based on the type of anions and cations that make up the ionic liquid. Depending on the cation parent, ionic liquids can be divided into imidazolium salts, pyridinium salts, quaternary ammonium salts, and quaternary phosphonium salts. The anions that make up ionic liquids are primarily halogens, chloroaluminates, and some larger anions containing fluorine. Ionic liquids can also be categorized into hydrophilic and hydrophobic ionic liquids based on their solubility in water.

[0003] By introducing long alkyl hydrophobic chains into the parent ionic liquids of "designable green solvents" and modifying the anion type, the ionic liquids are made both amphiphilic and highly active, creating a new type of surfactant. This new type of surfactant not only possesses the amphiphilic properties of traditional surfactants but also possesses the designability of ionic liquids. Therefore, they are also called "designable surfactants." They generally exhibit better surface activity in aqueous solutions than their traditional counterparts. Currently studied ionic liquid surfactants are primarily chemically synthesized from petroleum derivatives, and many ionic liquid surfactants containing heterocycles such as imidazole, pyridine, thiazole, quinoline, tetrahydropyrrole, and hexahydropyridine have been reported. These ionic liquid surfactants are mostly derived from petrochemical raw materials, resulting in high costs, complex synthesis processes, and the use of large amounts of toxic organic solvents. Therefore, there is an urgent need to develop new functionalized ionic liquid surfactants with simple preparation processes, low costs, and readily available green raw materials. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a cardanol-based ionic liquid surfactant, which solves the problems in the prior art that the raw materials of the ionic liquid surfactant are mostly petrochemical materials, the use cost is high, the synthesis process is complex, and a large amount of toxic organic solvents are required.

[0005] The technical solution adopted by the present invention is a method for preparing a cardanol-based ionic liquid surfactant, which is specifically implemented according to the following steps:

[0006] Step 1, preparation of benzoxazine structure intermediate

[0007] The raw materials, cardanol, glycine and paraformaldehyde, are mixed to form a mixture, and then the mixture is heated in an oil bath to obtain a layered solution. The upper layer of the layered solution is removed, and the lower layer product is collected and dried to obtain a white solid powder, which is a benzoxazine structure intermediate product;

[0008] Step 2, preparation of cardanol-based ionic liquid surfactant

[0009] A choline hydroxide solution is added dropwise to the benzoxazine structure intermediate product obtained in step 1, and methanol is added as a solvent to dissolve the benzoxazine structure intermediate product to obtain a dissolved reaction product, and then the solvent in the dissolved reaction product is removed by reduced pressure evaporation to obtain a light yellow viscous liquid at room temperature, which is then dried to obtain a cardanol-based ionic liquid surfactant.

[0010] Preferably, in step 1, cardanol, paraformaldehyde and glycine are mixed in a molar ratio of 1-2:1-2:2-4.

[0011] Preferably, the mixture in step 1 is prepared by adding raw materials, cardanol, glycine and paraformaldehyde, in proportion to a glass three-necked flask with mechanical stirring.

[0012] Preferably, the oil bath heating in step 1 is specifically as follows: placing a glass three-necked flask in an oil bath pot, installing a condensation reflux tube and opening the circulating condensed water, adding 30-40 mL of methanol as a solvent, then starting stirring and heating at the same time, when the oil bath temperature reaches 65 ° C., keeping the temperature constant for 6 hours, then stopping heating, cooling to room temperature, and obtaining a layered solution.

[0013] Preferably, the upper layer of the layered solution in step 1 is light yellow and the lower layer is milky white. The upper layer of the layered solution is removed, and ethyl acetate is added dropwise to the lower layer product for precipitation. The filter cake is collected and vacuum dried at 70° C. to obtain a white solid powder, which is the benzoxazine structure intermediate product.

[0014] Preferably, in step 2, 20-30 mL of methanol is added as a solvent, and 10-20 mL of an equimolar choline hydroxide solution with a mass concentration of 44 wt% is added dropwise.

[0015] Preferably, the temperature for dissolving the benzoxazine structure intermediate product in step 2 is room temperature.

[0016] Preferably, in step 2, the light yellow viscous liquid is placed in a vacuum drying oven at 50-60° C. and dried for 6-8 hours to obtain a brownish-yellow viscous liquid, which is the cardanol-based ionic liquid surfactant.

[0017] Preferably, the prepared cardanol-based ionic liquid surfactant has the following chemical structural formula:

[0018]

[0019] The beneficial effects of the present invention are:

[0020] (1) The present invention uses biomass materials cardanol and choline hydroxide as raw materials to prepare green, environmentally friendly and renewable functional ionic liquid surfactants. The raw materials are widely available and the preparation process is simple. It can reduce the production cost of traditional petrochemical raw materials and reduce dependence on fossil fuels. It is also in line with the current trend of sustainable development in society, promotes the development of a green and low-carbon economy, and also promotes the resource utilization of biomass raw materials.

[0021] (2) The present invention organically combines the characteristics of ionic liquids with the properties of surfactants. It has the low vapor pressure and green and pollution-free characteristics of ionic liquids, and the amphiphilicity of traditional surfactants. The surface tension and interfacial tension values ​​of the prepared ionic liquid surfactant can reach 34.8mN / m and 1.68mN / m respectively, and has excellent surface and interfacial activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a graph showing the change in surface tension of the cardanol-based ionic liquid surfactant obtained in Example 1 of the present invention as a function of concentration. DETAILED DESCRIPTION

[0023] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The preparation method of the cardanol-based ionic liquid surfactant of the present invention is to prepare the above-mentioned cardanol-based ionic liquid surfactant, specifically according to the following steps:

[0025] Step 1, preparation of benzoxazine structure intermediate

[0026] The raw materials, cardanol, paraformaldehyde and glycine, were added to a glass three-necked flask with mechanical stirring in a molar ratio of 1-2:1-2:2-4 to obtain a mixture. The glass three-necked flask was then placed in an oil bath, a condenser reflux tube was installed, and the circulating condensed water was turned on. 30-40 mL of methanol was added as a solvent, and then stirring was started while heating. When the oil bath temperature reached 65 ° C, the temperature was kept constant for 6 h, and then heating was stopped and cooled to room temperature to obtain a layered solution. The upper layer of the layered solution was light yellow and the lower layer was milky white. The upper layer of the layered solution was removed, and ethyl acetate was added dropwise to the lower layer product to precipitate. The filter cake was collected and vacuum dried at 70 ° C to obtain a white solid powder, which was a benzoxazine structure intermediate product;

[0027] Step 2, preparation of cardanol-based ionic liquid surfactant

[0028] To the benzoxazine structure intermediate obtained in step 1, 20-30 mL of methanol was added as a solvent, and 10-20 mL of an equimolar mass concentration of 44 wt% choline hydroxide solution was added dropwise to dissolve the benzoxazine structure intermediate at room temperature to obtain a dissolved reaction product, and then the solvent in the dissolved reaction product was removed by reduced pressure evaporation to obtain a light yellow viscous liquid at room temperature, and then the light yellow viscous liquid was placed in a vacuum drying oven at 50-60 ° C and dried for 6-8 h to obtain a brown viscous liquid, which is a cardanol-based ionic liquid surfactant.

[0029] The cardanol-based ionic liquid surfactant has the following chemical structure:

[0030]

[0031] Example 1

[0032] Step 1:

[0033] Take 3.03g of cardanol, 0.6g of paraformaldehyde and 0.75g of glycine, and put them into a 250mL glass three-necked flask with mechanical stirring in sequence to form a mixture; place the three-necked flask in an oil bath, install a condenser reflux tube and open the circulating condensed water, and add 30mL of methanol as a solvent. Then start stirring and heat at the same time. When the oil bath temperature reaches 65°C, keep the temperature constant for 6h, then stop heating and cool to room temperature to obtain a layered solution (the upper layer is light yellow and the lower layer is milky white). Finally, remove the upper liquid, add ethyl acetate to the lower layer product and precipitate it, collect the filter cake and vacuum dry it at 70°C to obtain a white solid powder, which is a benzoxazine structure intermediate product;

[0034] Step 2:

[0035] 1.2g of a 44wt% choline hydroxide solution was added dropwise to the benzoxazine intermediate, followed by the addition of 20mL of methanol as the solvent. The reaction was stirred at room temperature (approximately 25°C) until the intermediate was completely dissolved. After the reaction, the solvent was evaporated under reduced pressure at 65°C. The resulting product was a pale yellow viscous liquid at room temperature. The sample was then dried in a vacuum drying oven at 50°C for 6 hours to obtain a cardanol-based ionic liquid surfactant.

[0036] like Figure 1 As shown, when the surfactant concentration of the cardanol-based ionic liquid surfactant prepared in Example 1 reaches 0.009 g / mL, its surface tension value is as low as 34.8 mN / m, and the interfacial tension value at this concentration is 1.68 mN / m.

[0037] Example 2:

[0038] Step 1:

[0039] Take 6.06g of cardanol, 1.2g of paraformaldehyde and 1.5g of glycine, put them into a 250mL glass three-necked flask with mechanical stirring in sequence, and configure them into a mixture; place the three-necked flask in an oil bath, install a condensation reflux tube and open the circulating condensed water, add 35mL of methanol as a solvent, then start stirring and heat up at the same time. When the oil bath temperature reaches 65°C, keep the temperature constant for 6h, then stop heating and cool to room temperature to obtain a layered solution (the upper layer is light yellow and the lower layer is milky white). Finally, remove the upper liquid, add ethyl acetate to the lower layer product to precipitate, collect the filter cake and vacuum dry it at 70°C to obtain a white solid powder.

[0040] Step 2:

[0041] 2.4 g of a 44 wt% choline hydroxide solution was added dropwise to the benzoxazine intermediate, followed by the addition of 25 mL of methanol as a solvent. The reaction was stirred at room temperature (approximately 25°C) until the intermediate was completely dissolved. After the reaction, the solvent was evaporated under reduced pressure at 60°C. The resulting product was a pale yellow viscous liquid at room temperature. The sample was then dried in a vacuum drying oven at 55°C for 7 hours to obtain a cardanol-based ionic liquid surfactant.

[0042] The cardanol-based ionic liquid surfactant obtained in Example 2 has a minimum surface tension of 35.1 mN / m when its concentration reaches 0.009 g / mL, and the interfacial tension at this concentration is 1.72 mN / m.

[0043] Example 3:

[0044] Step 1:

[0045] Take 9.08g of cardanol, 1.8g of paraformaldehyde and 2.25g of glycine, put them into a 250mL glass three-necked flask with mechanical stirring in sequence, and configure them into a mixture; place the three-necked flask in an oil bath, install a condensation reflux tube and open the circulating condensed water, add 40mL of methanol as a solvent, then start stirring and heat up at the same time. When the oil bath temperature reaches 65°C, keep the temperature constant for 6h, then stop heating and cool to room temperature to obtain a layered solution (the upper layer is light yellow and the lower layer is milky white). Finally, remove the upper liquid, add ethyl acetate to the lower layer product to precipitate, collect the filter cake and vacuum dry it at 70°C to obtain a white solid powder.

[0046] Step 2:

[0047] 3.64 g of a 44 wt% choline hydroxide solution was added dropwise to the benzoxazine intermediate. 30 mL of methanol was added as the solvent and stirred at room temperature (approximately 25°C) until the intermediate was completely dissolved. After the reaction, the solvent was evaporated under reduced pressure at 60°C. The resulting product was a pale yellow viscous liquid at room temperature. The sample was then dried in a vacuum drying oven at 60°C for 8 hours to obtain a cardanol-based ionic liquid surfactant.

[0048] The cardanol-based ionic liquid surfactant obtained in Example 3 has a minimum surface tension of 35.3 mN / m when its concentration reaches 0.009 g / mL, and the interfacial tension at this concentration is 1.81 mN / m.

[0049] The method of the present invention can be used to obtain a cardanol-based ionic liquid surfactant. The ionic liquid surfactant prepared by the present invention is green, environmentally friendly, renewable, and inexpensive, providing a fruitful idea and method for the development and utilization of functionalized ionic liquids.

Claims

1. A method for preparing a cardanol-based ionic liquid surfactant, characterized in that: The specific implementation steps are as follows: Step 1, preparation of benzoxazine structure intermediate The raw materials, cardanol, glycine and paraformaldehyde, are mixed to form a mixture, and then the mixture is heated in an oil bath to obtain a layered solution. The upper layer of the layered solution is removed, and the lower layer product is collected and dried to obtain a white solid powder, which is a benzoxazine structure intermediate product; Step 2, preparation of cardanol-based ionic liquid surfactant Adding choline hydroxide solution dropwise to the benzoxazine structure intermediate product obtained in step 1, and adding methanol as a solvent to dissolve the benzoxazine structure intermediate product to obtain a dissolved reaction product, and then removing the solvent in the dissolved reaction product by reduced pressure evaporation to obtain a light yellow viscous liquid at room temperature, and then drying to obtain a cardanol-based ionic liquid surfactant; The cardanol-based ionic liquid surfactant has the following chemical structural formula: 。 2. The method for preparing the cardanol-based ionic liquid surfactant according to claim 1, wherein In the step 1, cardanol, paraformaldehyde and glycine are mixed in a molar ratio of 1-2:1-2:2-4.

3. The preparation method of the cardanol-based ionic liquid surfactant according to claim 2, wherein The mixture in step 1 is prepared by adding raw materials, cardanol, glycine and paraformaldehyde according to proportion into a glass three-necked flask with mechanical stirring.

4. The method for preparing the cardanol-based ionic liquid surfactant according to claim 3, wherein The oil bath heating in step 1 is specifically as follows: a glass three-necked flask is placed in an oil bath, a condenser reflux tube is installed and the circulating condensed water is turned on, 30-40 mL of methanol is added as a solvent, and then stirring is started while heating. When the oil bath temperature reaches 65°C, the temperature is kept constant for 6 hours, and then heating is stopped and cooled to room temperature to obtain a layered solution.

5. The method for preparing the cardanol-based ionic liquid surfactant according to claim 4, wherein In step 1, the upper layer of the layered solution is light yellow and the lower layer is milky white. The upper layer of the layered solution is removed, and ethyl acetate is added dropwise to the lower layer product for precipitation. The filter cake is collected and vacuum dried at 70° C. to obtain a white solid powder, which is the benzoxazine structure intermediate product.

6. The method for preparing the cardanol-based ionic liquid surfactant according to claim 5, wherein In step 2, 20-30 mL of methanol was added as a solvent, and 10-20 mL of an equimolar mass concentration of 44 wt% choline hydroxide solution was added dropwise.

7. The method for preparing the cardanol-based ionic liquid surfactant according to claim 6, wherein The temperature for dissolving the benzoxazine structure intermediate product in step 2 is room temperature.

8. The method for preparing the cardanol-based ionic liquid surfactant according to claim 7, wherein In the step 2, the light yellow viscous liquid is placed in a vacuum drying oven at 50-60° C. and dried for 6-8 hours to obtain a brownish-yellow viscous liquid, which is the cardanol-based ionic liquid surfactant.

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