Preparation method of cardanol-based ionic liquid surfactant

Abstract

The invention discloses a preparation method of an anacardol-based ionic liquid surfactant, which is specifically implemented according to the following steps: step 1, preparing a mixture from raw materials of anacardol, glycine and paraformaldehyde, performing oil bath heating to obtain a layered solution, and removing supernatant of the layered solution to obtain an anacardol-based ionic liquid surfactant; drying the lower-layer product to obtain a benzoxazine structure intermediate product; and 2, dropwise adding a choline hydroxide solution into the benzoxazine structure intermediate product, adding methanol as a solvent to obtain a dissolved reaction product, removing the solvent in the dissolved reaction product to obtain a light yellow viscous liquid at room temperature, and drying to obtain the cardanol-based ionic liquid surfactant. The problems that in the prior art, most raw materials of an ionic liquid surfactant are petrochemical materials, the use cost is high, the synthesis process is complex, and a large number of toxic organic solvents are needed are solved.

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 the increasing awareness of environmental protection, people have gradually paid attention to the use of non-toxic green solvents to replace organic solvents. Various green solvents such as water, supercritical fluids and ionic liquids have attracted widespread attention. Among them, ionic liquids, as a new type of green solvent, are salts in a molten state that are completely composed of organic or inorganic ions. Due to its advantages such as low volatility, good thermal stability and strong structural designability, it is called "designable green solvent" and has developed rapidly in recent decades. There are many types of ionic liquids. According to the types of anions and cations that make up the ionic liquids, ionic liquids can be simply classified. According to the different cation matrix, ionic liquids can be divided into imidazolate salts, pyridinium salts, quaternary ammonium salts and quaternary phosphonium salts. The anions that constitute ionic liquids are mainly halogens, chloroaluminates, and some fluorine-containing and large anions. Ionic liquids can also be divided into hydrophilic ionic liquids and hydrophobic ionic liquids according to their different solubility in water.

[0003] By introducing long alkyl hydrophobic chains into the parent of "designable green solvent" ionic liquid and changing the type of anion, the ionic liquid has both amphiphilicity and good surface activity, becoming a new type of surfactant. This new type of surfactant not only has the amphiphilic properties of traditional surfactants, but also has the designability of ionic liquids. Therefore, it is also called "designable surfactant". They usually show better surface activity in aqueous solution than similar traditional surfactants. The ionic liquid surfactants currently studied are mainly chemically synthesized from petroleum derivatives. Many ionic liquid surfactants containing heterocyclic rings such as imidazole, pyridine, thiazole, quinoline, tetrahydropyrrole and hexahydropyridine have been reported. The raw materials of this type of ionic liquid surfactant are mostly petrochemical materials, with high cost of use, complex synthesis process, and the need to use a large amount of toxic organic solvents. Therefore, it is urgent to develop new functionalized ionic liquid surfactants with simple preparation process, low cost, and green and easy-to-obtain 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 problem that the raw materials of the ionic liquid surfactants in the prior art are mostly petrochemical materials, the use cost is high, the synthesis process is complicated, 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 of 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 into 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, and 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 of cardanol, glycine and paraformaldehyde in proportion into 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, ethyl acetate is added dropwise to the lower layer product for precipitation, and the filter cake is collected and vacuum dried at 70° C. to obtain a white solid powder, which is a benzoxazine structure intermediate product.

[0014] Preferably, in step 2, 20-30 mL of methanol is added as a solvent, and 10-20 mL of a choline hydroxide solution having an equimolar 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, and has both 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 34.8 mN / m and 1.68 mN / m, respectively, and have excellent surface and interfacial activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a curve diagram of 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 is 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 cardanol-based ionic liquid surfactant, and the preparation is specifically carried out according to the following steps:

[0025] Step 1, preparation of benzoxazine structure intermediate

[0026] The raw materials of cardanol, polyformaldehyde and glycine are 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, and then the glass three-necked flask is placed in an oil bath, a condensation 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 turned on while heating, when the oil bath temperature reaches 65°C, the temperature is kept constant for 6 hours, and then the heating is stopped and cooled to room temperature to obtain a layered solution, 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, ethyl acetate is dripped into the lower layer product for precipitation, and the filter cake is collected and vacuum dried at 70°C to obtain a white solid powder, which is a benzoxazine structure intermediate product;

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

[0028] To the benzoxazine structure intermediate product obtained in step 1, 20-30 mL of methanol is added as a solvent, and 10-20 mL of an equimolar mass concentration of 44 wt% choline hydroxide solution is added dropwise to dissolve the benzoxazine structure intermediate product at room temperature 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, and then 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 brown-yellow 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 prepare a mixture; put the three-necked flask into an oil bath, install a condensation reflux tube and turn on the circulating condensed water, and add 30mL 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, cool to room temperature, and obtain a layered solution (the upper layer is light yellow and the lower layer is milky white), finally remove the upper layer liquid, drop ethyl acetate into the lower layer product to precipitate, 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] 1.2 g of 44 wt% choline hydroxide solution was dripped into the intermediate product of benzoxazine structure and 20 mL of methanol was added as solvent, and the reaction was continued at room temperature (about 25° C.) until the intermediate product was completely dissolved. After the reaction was completed, the solvent was evaporated under reduced pressure at 65° C., and the obtained product was a light yellow viscous liquid at room temperature. After that, the sample was placed in a vacuum drying oven at 50° C. and dried 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] Embodiment 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 turn, and configure them into a mixture; put the three-necked flask into an oil bath pot, 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, cool to room temperature, and obtain a layered solution (the upper layer is light yellow and the lower layer is milky white). Finally, remove the upper liquid, drip ethyl acetate into the lower layer product for precipitation, collect the filter cake and vacuum dry it at 70°C to obtain a white solid powder.

[0040] Step 2:

[0041] Take 2.4g of 44wt% choline hydroxide solution, drip it dropwise into the intermediate product of benzoxazine structure and add 25mL methanol as solvent, and stir continuously at room temperature (about 25°C) until the intermediate product is completely dissolved. After the reaction is completed, the solvent is evaporated under reduced pressure at 60°C, and the obtained product is a light yellow viscous liquid at room temperature. After that, the sample is placed in a vacuum drying oven at 55°C and dried for 7h 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 the concentration reaches 0.009 g / mL, and the interfacial tension value at this concentration is 1.72 mN / m.

[0043] Embodiment 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 turn, and configure them into a mixture; put the three-necked flask into an oil bath pot, install a condensation reflux tube and open the circulating condensed water, add 40mL of methanol as a solvent, then turn on 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, cool to room temperature, and obtain a layered solution (the upper layer is light yellow and the lower layer is milky white). Finally, remove the upper liquid, drip ethyl acetate into the lower layer product for precipitation, 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 44 wt% choline hydroxide solution was added dropwise into the intermediate product of the benzoxazine structure and 30 mL of methanol was added as a solvent. The reaction was continued at room temperature (about 25° C.) until the intermediate product was completely dissolved. After the reaction was completed, the solvent was evaporated under reduced pressure at 60° C. The obtained product was a light yellow viscous liquid at room temperature. The sample was then placed in a vacuum drying oven at 60° C. and dried for 8 h 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 the concentration reaches 0.009 g / mL, and the interfacial tension value 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, and provides 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 steps are as follows: Step 1, preparation of benzoxazine structure intermediate The raw materials of 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 A choline hydroxide solution is added dropwise into 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, and then dried to obtain a cardanol-based ionic liquid surfactant.

2. The method for preparing the cardanol-based ionic liquid surfactant according to claim 1, characterized in that: In the step 1, cardanol, paraformaldehyde and glycine are mixed in a molar ratio of 1-2:1-2:2-4.

3. The method for preparing the cardanol-based ionic liquid surfactant according to claim 2, characterized in that: The mixture in step 1 is prepared by adding raw materials of cardanol, glycine and paraformaldehyde in 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, characterized in that: The oil bath heating in step 1 is specifically as follows: a glass three-necked flask is placed in an oil bath pot, a condensation 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 turned on 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, characterized in that: In the 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 a benzoxazine structure intermediate product.

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

7. The method for preparing the cardanol-based ionic liquid surfactant according to claim 6, characterized in that: 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, characterized in that: 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.

9. The method for preparing the cardanol-based ionic liquid surfactant according to claim 7, characterized in that: The cardanol-based ionic liquid surfactant has the following chemical structural formula:

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