A piperazine-based surface active ionic liquid aqueous two-phase system, a preparation method and application thereof

Abstract

The application discloses a piperazine-based surface-active ionic liquid double-water phase system, a preparation method and application thereof, and belongs to the field of ionic liquid double-water phase systems. 17 The piperazine-based surface-active ionic liquid double-water phase system comprises a piperazine-based surface-active ionic liquid, a cationic surfactant and water; the piperazine-based surface-active ionic liquid has the following general chemical structure: wherein R1 is ethyl, n-propyl, isopropyl, hydroxyethyl or hydroxypropyl, R2 is a linear alkyl group with 7-15 carbon atoms, and R3 is a linear alkyl group with 8-18 carbon atoms. 12 The application further discloses application of the piperazine-based surface-active ionic liquid double-water phase system in extraction of small-molecule organic substances. The piperazine-based surface-active ionic liquid double-water phase system disclosed by the application has the advantages of rapid and simple preparation, low cost, wide polarity range, high environmental safety, high extraction efficiency and extraction selectivity in extraction of small-molecule organic substances, and can be applied to the fields of drug extraction and sewage treatment, and has great application prospect.

Description

Technical Field

[0001] This invention belongs to the field of separation technology for aqueous two-phase systems, specifically referring to a piperazine-based surface-active ionic liquid aqueous two-phase system, its preparation method, and its application. Background Technology

[0002] Aqueous two-phase systems are a novel type of separation and reaction medium, consisting of two layers due to their different densities. Aqueous two-phase systems exhibit very low interfacial tension, providing a mild environment for bioactive substances and preventing contamination during processes such as drug extraction and purification, and the separation and purification of biological components. Ionic liquid aqueous two-phase systems combine the characteristics of ionic liquids and aqueous two-phase systems, including: (1) high water content and mild operating conditions; (2) low interfacial tension, which helps maintain the activity of biomolecules; (3) no pollution problems from volatile organic solvents; (4) ease of process scale-up and continuous operation; and (5) high tunability of system properties. However, the formation of aqueous two-phase systems lacks clear regularity and is unpredictable, limiting their research and application.

[0003] Compared to ordinary ionic liquids, surfactant ionic liquids possess the ability to form self-assembled structures. Structures such as micelles and vesicles can solubilize poorly soluble components, improving separation and extraction performance. Compared to inorganic salts and ordinary ionic surfactants, surfactant ionic liquids have less exposed charge, making it easier to adjust the interaction strength. Compared to nonionic surfactants and polymers, surfactant ionic liquids have a wider range of polarity and affinity. Currently, many reports in the literature utilize imidazole or pyridine ionic liquids with inorganic salts or surfactants to form aqueous two-phase systems. For example, patent publication CN111537456A provides a method for forming an aqueous two-phase system using an imidazole ionic liquid and an inorganic salt, and its application in determining the hydrophobicity of organic matter. Patent publication CN110863106A provides a method for extracting copper ions using an ionic liquid aqueous two-phase system formed by imidazole or pyridine ionic liquids with Na3PO4 or NaH2PO4. Similarly, patent document CN108484465A discloses a method for extracting astaxanthin from Haematococcus pluvialis using an aqueous two-phase system composed of an imidazole-based ionic liquid, the surfactant Tritonx-100, and sodium dodecyl sulfate. Because the composition of a system is closely related to its application scenario, a single system can generally only be used for the extraction of a certain type of substance. Therefore, it is essential to develop novel aqueous two-phase ionic liquid systems with good performance, high environmental safety, and low cost for specific extraction targets. Summary of the Invention

[0004] In view of this, the first objective of the present invention is to propose a piperazine-based surface-active ionic liquid aqueous two-phase system.

[0005] The second objective of this invention is to provide a method for preparing the above-mentioned piperazine-based surface-active ionic liquid aqueous two-phase system.

[0006] The third objective of this invention is to propose the application of the above-mentioned piperazine-based surface-active ionic liquid aqueous two-phase system.

[0007] To solve the above-mentioned technical problems, the present invention is implemented through the following technical solution:

[0008] A piperazine-based surfactant ionic liquid aqueous two-phase system comprises a piperazine-based surfactant ionic liquid, a cationic surfactant, and water. The mass fraction of the piperazine-based surfactant in the system is 0.50%–30.00%, the mass fraction of the cationic surfactant is 0.50%–20.00%, and the mass fraction of water is 50.00%–99.00%.

[0009] The piperazine-based surfactant ionic liquid has the following general chemical structural formula:

[0010]

[0011] Wherein, R1 is ethyl, n-propyl, isopropyl, hydroxyethyl, or hydroxypropyl, and R2 is a compound of the general formula C2. n H 2n+1 Straight-chain alkyl groups, n is 7 to 17, and R3 is a compound of the general formula C n H 2n+1 Straight-chain alkyl groups, n is 8 to 12.

[0012] The cationic surfactant is selected from 1-dodecyl-3-methylimidazolium chloride, 1-dodecyl-3-methylimidazolium bromide, dodecyltrimethylammonium chloride, dodecyldimethylbenzylammonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, tetradecyldimethylbenzylammonium chloride, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, hexadecyldimethylbenzylammonium chloride, etc.

[0013] The preparation method of the above-mentioned piperazine-based surfactant ionic liquid aqueous two-phase system includes the following steps:

[0014] Piperazine-based surfactant ionic liquid, cationic surfactant, and water were mixed in a specific ratio and allowed to stand at room temperature for a certain period of time, resulting in stratification. The final system contained 0.50%–30.00% ionic liquid, 0.50%–20.00% surfactant, and 50.00%–99.00% water by mass.

[0015] Furthermore, the molar ratio of the piperazine-based surfactant ionic liquid to the surfactant is from 1:0.9 to 1:1.9.

[0016] Furthermore, after the piperazine-based surfactant and the cationic surfactant are mixed with water, the mixture is allowed to stand for 0 to 2 days.

[0017] The piperazine-based surface-active ionic liquid aqueous two-phase system of the present invention can be applied to the extraction of small organic molecules and is used in fields such as drug extraction and wastewater treatment.

[0018] The beneficial effects of the above-described technical solution of the present invention are as follows:

[0019] The piperazine-based surfactant ionic liquid aqueous two-phase system described in this invention is simple to prepare, environmentally safe, and low in cost. A high-water-content, mild aqueous two-phase system can be obtained by mixing the ionic liquid, surfactant, and a certain amount of water. This piperazine-based surfactant ionic liquid aqueous two-phase system can also be used to extract small organic molecules and has significant potential applications in drug extraction, wastewater treatment, and other fields. Attached Figure Description

[0020] Figure 1 Photograph of the hexadecyltrimethylammonium bromide / 1-(2-hydroxyethyl)piperazine tetradecanoate / water triaqueous system in Application Example 1.

[0021] Figure 2 Photographs showing the extraction of Brilliant Blue using the dodecyltrimethylammonium bromide / 1-n-propylpiperazine tetradecanoate / water system in Example 2. Detailed Implementation

[0022] To make the technical problems, technical solutions, and advantages of this invention clearer, a detailed description will be provided below in conjunction with specific embodiments. However, these embodiments should not be construed as limiting the scope of this invention under any circumstances.

[0023] The method for preparing the piperazine-based surfactant ionic liquid aqueous two-phase system of the present invention includes the following steps:

[0024] When piperazine-based surfactant ionic liquids and cationic surfactants are mixed at a certain molar ratio and water is added to a certain total water content, and the mixture is left to stand at room temperature (25°C) for a period of time, stratification can be observed.

[0025] The general chemical structural formula of the piperazine-based surfactant ionic liquid is as follows:

[0026]

[0027] Wherein, R1 is hydroxyethyl or hydroxypropyl, and can also be ethyl, n-propyl, or isopropyl; R2 is a compound with the general formula C n H 2n+1 Straight-chain alkyl groups, n is 7–17; R3 is a group with the general formula C n H2n+1 Straight-chain alkyl groups, n is 8 to 12.

[0028] The cationic surfactant is selected from at least one of 1-dodecyl-3-methylimidazolium chloride, 1-dodecyl-3-methylimidazolium bromide, dodecyltrimethylammonium chloride, dodecyldimethylbenzylammonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, tetradecyldimethylbenzylammonium chloride, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, and hexadecyldimethylbenzylammonium chloride.

[0029] The molar ratio of the piperazine-based surfactant to the cationic surfactant is from 1:0.9 to 1:1.9.

[0030] The content of the piperazine-based surfactant in the aqueous two-phase mixture ranges from 0.50% to 30.00%, the content of the cationic surfactant ranges from 0.50% to 20.00%, and the water content ranges from 50.00% to 99.00%.

[0031] In the preparation process of this invention, the morphology of the product varies depending on the selected component types and the amount of water added. Even with the same component selection, changing the water content in the system may also alter the product's state. For example, adding a certain water content may result in a turbid product; further addition may lead to a two-phase aqueous state; and further addition may result in a three-phase aqueous state or a turbid state again. Therefore, the final state of the product obtained during the preparation of this invention is related to the selected component types and water content. The following examples illustrate this process.

[0032] Example cationic surfactants Piperazine-based surface-active ionic liquids Water content 1 Hexadecyltrimethylammonium bromide 1-(2-hydroxyethyl)piperazine tetradecanoate 65.68％ 2 Dodecyltrimethylammonium bromide 1-n-Propylpiperazine dodecanoate 82.65％ 3 Hexadecyltrimethylammonium chloride 1-Isopropylpiperazine dodecanoate 77.38％ 4 Dodecyl dimethyl benzyl ammonium chloride 1-(2-hydroxyethyl)piperazine decyl sulfate 95.35％ 5 1-Dodecyl-3-methylimidazolium chloride 1-(2-hydroxyethyl)piperazine dodecyl sulfate 83.60％

[0033] Example 1

[0034] The preparation of the piperazine-based surface-active ionic liquid aqueous two-phase system in this embodiment is as follows:

[0035] (1) Prepare a 0.6 mol / L aqueous solution of both hexadecyltrimethylammonium bromide and 1-(2-hydroxyethyl)piperazine tetradecanoate;

[0036] (2) Mix the above aqueous solution so that the molar ratio of 1-(2-hydroxyethyl)piperazine tetradecanoate to hexadecyltrimethylammonium bromide is 1:0.95;

[0037] (3) Add water until the total water content in the system is 65.68 wt%, mix thoroughly, and reach phase equilibrium after 18 hours.

[0038] Example 2

[0039] The preparation of the piperazine-based surface-active ionic liquid aqueous two-phase system in this embodiment is as follows:

[0040] (1) Prepare 0.5 mol / L aqueous solutions of both dodecyltrimethylammonium bromide and 1-n-propylpiperazine dodecanoate;

[0041] (2) Mix the above aqueous solution so that the molar ratio of 1-n-propylpiperazine dodecanoate to dodecyltrimethylammonium bromide is 1:1.70;

[0042] (3) Add water until the total water content in the system is 82.65 wt%, mix thoroughly, and reach phase equilibrium after 6 hours.

[0043] Example 3

[0044] The preparation of the piperazine-based surface-active ionic liquid aqueous two-phase system in this embodiment is as follows:

[0045] (1) Prepare 0.5 mol / L aqueous solutions of both hexadecyltrimethylammonium chloride and 1-isopropylpiperazine dodecanoate;

[0046] (2) Mix the above aqueous solution so that the molar ratio of 1-isopropylpiperazine dodecanoate to hexadecyltrimethylammonium chloride is 1:1.22;

[0047] (3) Add water until the total water content in the system is 77.38 wt%, mix thoroughly, and reach phase equilibrium after 48 h.

[0048] Example 4

[0049] The preparation of the piperazine-based surface-active ionic liquid aqueous two-phase system in this embodiment is as follows:

[0050] (1) Prepare 0.6 mol / L aqueous solutions of both dodecyl dimethyl benzyl ammonium chloride and 1-(2-hydroxyethyl)piperazine decyl sulfate;

[0051] (2) Mix the above aqueous solution so that the molar ratio of 1-(2-hydroxyethyl)piperazine decyl sulfate to dodecyl dimethyl benzyl ammonium chloride is 1:1.35;

[0052] (3) Add water until the total water content in the system is 95.35 wt%, mix thoroughly, and reach phase equilibrium after 24 hours.

[0053] Example 5

[0054] The preparation of the piperazine-based surface-active ionic liquid aqueous two-phase system in this embodiment is as follows:

[0055] (1) Prepare 0.5 mol / L aqueous solutions of both 1-dodecyl-3-methylimidazolium chloride and 1-(2-hydroxyethyl)piperazine dodecyl sulfate;

[0056] (2) Mix the above aqueous solution so that the molar ratio of 1-(2-hydroxyethyl)piperazine dodecyl sulfate to 1-dodecyl-3-methylimidazolium chloride is 1:1.16;

[0057] (3) Add water until the total water content in the system is 83.60 wt%, mix thoroughly, and reach phase equilibrium after 24 hours.

[0058] Application Example 1

[0059] By adjusting the ratio of piperazine-based surfactant ionic liquid, cationic surfactant, and water, a three-phase aqueous system can be formed through the following steps:

[0060] Water was added to the system described in Example 1 until the total water content reached 97.30 wt%. After thorough mixing, phase equilibrium was reached after 48 hours, and the two-phase system transformed into a three-phase system. This demonstrates that adjusting the water content can change the state of the system while keeping the components constant.

[0061] Application Example 2

[0062] A two-phase system prepared from dodecyltrimethylammonium bromide and 1-n-propylpiperazine dodecanoate was used to extract Brilliant Blue, and the following steps were performed:

[0063] In Example 2, 10 -4 A two-phase system of dodecyltrimethylammonium bromide / 1-n-propylpiperazine dodecanoate / water was prepared by replacing pure water with a mol / L brilliant blue aqueous solution. After phase equilibrium was reached, brilliant blue was visible to the naked eye in the upper phase. The upper and lower phases were filtered through 3.0 μm filter membranes, and the extraction rate of brilliant blue was measured at 630 nm using a UV spectrophotometer. The calculated extraction rate was 99.46%.

[0064] Application Example 3

[0065] A two-phase system prepared from hexadecyltrimethylammonium chloride and 1-isopropylpiperazine dodecanoate was used to extract curcumin, and the following steps were performed:

[0066] 0.2 mg / g of curcumin was added to the hexadecyltrimethylammonium chloride / 1-isopropylpiperazine dodecanoate / water aqueous two-phase system prepared in Example 3, and the sample was thoroughly shaken to mix. After phase equilibrium was reached, curcumin was visible to the naked eye in the upper phase. The upper and lower phases were filtered through a 3.0 μm filter membrane, and the results were measured at 425 nm using a UV spectrophotometer. The extraction rate of curcumin was calculated to be 95.21%.

[0067] Application Example 4

[0068] A two-phase system prepared from dodecyl dimethyl benzyl ammonium chloride and 1-(2-hydroxyethyl)piperazine decyl sulfate was used to extract Allura Red, and the following steps were performed:

[0069] In Example 4, 10 -4 A two-phase system of dodecyl dimethyl benzyl ammonium chloride / 1-(2-hydroxyethyl)piperazine decyl sulfate / water was prepared by replacing pure water with an aqueous solution of Allura Red in mol / L. After phase equilibrium was reached, Allura Red was visible to the naked eye in the upper phase. The upper and lower phases were filtered through 3.0 μm filter membranes and measured at 504 nm using a UV spectrophotometer. The extraction rate of Allura Red was calculated to be 99.07%.

[0070] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A piperazinyl surfactant ionic liquid aqueous two-phase system, characterized in that, The system comprises a piperazinyl surface-active ionic liquid, a cationic surfactant and water, the piperazinyl surface-active ionic liquid has a general chemical structure formula as follows: or ; wherein R1 is ethyl, n-propyl, isopropyl, hydroxyethyl or hydroxypropyl, R2 is a linear alkyl group of the general formula C n H 2n+1 n is 7 to 17, and R3 is a linear alkyl group of the general formula C n H 2n+1 n is 8 to 12; The cationic surfactant is selected from 1-dodecyl-3-methylimidazolium chloride, 1-dodecyl-3-methylimidazolium bromide, dodecyltrimethylammonium chloride, dodecyl dimethyl benzyl ammonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, tetradecyl dimethyl benzyl ammonium chloride, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, and hexadecyl dimethyl benzyl ammonium chloride.

2. A piperazinyl surfactant ionic liquid aqueous two-phase system according to claim 1, wherein, The mass fraction of the piperazinyl surface-active ionic liquid in the system is 0.50% to 30.00%, the mass fraction of the cationic surfactant is 0.50% to 20.00%, and the mass fraction of water is 50.00% to 99.00%.

3. The method for preparing a piperazinyl surfactant ionic liquid aqueous two- phase system according to claim 1 or 2, characterized in that, The system comprises the following steps: The piperazinyl surface-active ionic liquid, the cationic surfactant and water are mixed in proportion, and phase equilibrium is reached after standing for a certain time at room temperature, and stratification can be observed.

4. The method for preparing a piperazine-based surface-active ionic liquid aqueous two-phase system as described in claim 3, characterized in that, The molar ratio of the piperazinyl surface-active ionic liquid to the cationic surfactant ranges from 1:0.9 to 1:1.

9.

5. The method for preparing a piperazine-based surface-active ionic liquid aqueous two-phase system as described in claim 3, characterized in that, The standing time for phase equilibrium is 0 to 2 days.

6. The method for preparing a piperazine-based surface-active ionic liquid aqueous two-phase system as described in claim 3, characterized in that, The mass fraction of the piperazinyl surface-active ionic liquid in the final system is 0.50% to 30.00%, the mass fraction of the cationic surfactant is 0.50% to 20.00%, and the mass fraction of water is 50.00% to 99.00%.

7. Use of a piperazinyl surface-active ionic liquid aqueous two-phase system as claimed in claim 1 or 2 as an extractant for extracting small organic molecules.

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