A ternary supramolecular deep eutectic solvent and a preparation method and application thereof

Abstract

This invention discloses a ternary supramolecular eutectic solvent, its preparation method, and its applications. The ternary supramolecular eutectic solvent is composed of a hydrogen bond acceptor, a hydrogen bond donor, and a silver salt. In application, the solvent is mixed with vegetable oil, and through assisted enhanced extraction, phase separation, and back-extraction, high-purity squalene can be obtained efficiently. This invention utilizes the synergistic effect of the hydrophobic inclusion of cyclodextrin and the specific complexation of double bonds by silver ions, significantly enhancing the targeted binding and separation ability of squalene. This solvent system is green and low in toxicity, simple to prepare, and the extraction method is highly efficient and selective. The solvent can be recycled, overcoming the shortcomings of existing technologies such as low extraction efficiency, high pollution, and high cost. It has broad application prospects in the field of green extraction of plant-derived squalene.

Description

Technical Field

[0001] This invention belongs to the field of biotechnology, and further to the field of natural product separation and purification and green solvent technology. Specifically, it relates to a ternary supramolecular eutectic solvent and its preparation method and application. Background Technology

[0002] Squalene is a highly unsaturated triterpenoid compound with significant physiological activity, exhibiting remarkable effects in enhancing immunity, antioxidation, anti-tumor activity, and improving skin health, and holds broad application prospects in the pharmaceutical, health product, and cosmetic fields. Currently, the commercial source of squalene is mainly limited to deep-sea shark liver oil, which not only threatens the survival of shark populations and raises serious ecological and ethical issues, but also poses a risk of marine pollutant accumulation. Therefore, developing sustainable extraction technologies for plant-derived squalene (such as those found in olive oil, macadamia nut oil, and other vegetable oils) has become an urgent need for the industry.

[0003] However, the efficient separation of squalene from vegetable oils faces significant challenges. Squalene has a long molecular chain, is extremely hydrophobic, and has similar physicochemical properties to major components of oils such as triglycerides, resulting in significant limitations of traditional separation methods. Currently, the main methods for extracting squalene from vegetable oils are as follows: (1) Molecular distillation or rectification (CN102089263A, US20130209510A1). This method uses the boiling point difference to separate and purify squalene, but the squalene obtained by this method has high energy consumption and is not easy to separate from compounds with similar boiling points, resulting in low purity of squalene; (2) Molecular crystallization and multi-stage solvent extraction (CN101830770A, CN102146014A). This method involves first saponifying the vegetable oil, then performing molecular distillation, and then enriching the squalene through multi-stage solvent extraction. This saponification and re-extraction method consumes a large amount of organic solvents, which not only significantly increases production costs but also causes serious environmental pollution problems; (3) Silver nitrate silica gel chromatography (CN104262076B). This method utilizes silver ions to form complexes with olefins (π electrons) to selectively separate squalene. This method requires a large amount of chromatographic packing material and organic eluent, which also leads to increased costs and environmental pollution problems. CN106748615A discloses a process technology for extracting squalene using cyclodextrin inclusion technology, but this method requires pretreatment of oil raw materials and ethanol reflux to de-inclusion operation, which also increases production costs. Therefore, it is crucial to develop new separation materials and processes that combine high selectivity, high efficiency and green environmental protection. Summary of the Invention

[0004] The first objective of this invention is to provide a ternary supramolecular eutectic solvent; the second objective is to provide a method for preparing the ternary supramolecular eutectic solvent; and the third objective is to provide applications of the ternary supramolecular eutectic solvent.

[0005] The first objective of this invention is achieved by the fact that the ternary supramolecular eutectic solvent is composed of hydrogen bond acceptors, hydrogen bond donors and silver salts.

[0006] The ternary supramolecular eutectic solvent described in this invention, as a novel green solvent, offers new insights for natural product extraction due to its designable physicochemical properties and good biocompatibility. Among them, the cyclodextrin-based supramolecular eutectic solvent combines the host-guest inclusion ability of cyclodextrin with the green characteristics of eutectic solvents, theoretically allowing for the inclusion of hydrophobic molecules such as squalene through its hydrophobic cavities. However, relying solely on the inclusion effect of cyclodextrin, its selectivity and extraction efficiency remain insufficient when dealing with complex vegetable oil systems.

[0007] Given the unique structural feature of squalene molecules containing multiple carbon-carbon double bonds, metal coordination offers a promising avenue for achieving highly selective extraction. Silver ions have attracted significant attention due to their potent and specific π-complexation with carbon-carbon double bonds. A ternary supramolecular eutectic solvent prepared by introducing silver ions can achieve specific recognition and robust binding of the target molecule, squalene. This promises to enable highly selective and efficient extraction of squalene from complex plant oil matrices, providing a green technological solution to the industry challenge of separating plant-derived squalene.

[0008] The second objective of this invention is achieved by homogenizing a mixture of hydrogen bond acceptors, hydrogen bond donors and silver salts in the specified formulation.

[0009] The third objective of this invention is achieved by the application of the ternary supramolecular eutectic solvent in the method for extracting squalene from vegetable oils.

[0010] This invention utilizes a supramolecular eutectic solvent to achieve precise and efficient separation of squalene through a synergistic effect of host-guest inclusion and metal coordination. Specifically, silver ions can specifically recognize squalene molecules containing multiple double bonds through complexation with carbon-carbon double bonds, thus improving separation purity. The hydrophobic cavities of cyclodextrin can encapsulate hydrophobic squalene molecules to form stable complexes, further enhancing separation efficiency.

[0011] The beneficial effects of this invention are as follows: 1. High Selectivity and High Efficiency: This invention combines the hydrophobic cavity inclusion effect of cyclodextrin with the specific π-complexation effect of silver ions on carbon-carbon double bonds to construct a ternary supramolecular eutectic solvent. The two components produce a synergistic effect, significantly enhancing the targeted recognition and binding ability of squalene molecules, thereby achieving highly selective and efficient extraction of squalene from complex vegetable oil matrices, with an extraction rate exceeding 96% and a purity higher than 98%.

[0012] 2. Green, environmentally friendly, and low-cost: The ternary supramolecular eutectic solvent of this invention is mainly composed of natural products or low-toxicity compounds, with low vapor pressure and good biocompatibility, avoiding the environmental pollution and safety hazards caused by the use of large amounts of volatile organic solvents (such as petroleum ether and n-hexane) in traditional methods. Furthermore, this method eliminates the need for complex pretreatment of vegetable oils such as saponification and enzymatic hydrolysis, and also eliminates the need for expensive chromatographic packing materials, resulting in a simple process and low energy consumption.

[0013] 3. Recyclable and reusable: The ternary supramolecular eutectic solvent can be separated from the product through a simple back-extraction operation and recycled for reuse. Experiments show that even after five cycles, its extraction efficiency for squalene remains at a high level, significantly reducing the consumption of precious metal silver and the overall process cost, which aligns with the concepts of green chemistry and sustainable development.

[0014] 4. Simple operation and easy to scale up: The entire extraction process can be carried out at room temperature and pressure. The main operating units are mixing, auxiliary enhancement (such as shearing and ultrasonication) and centrifugation. No special equipment is required, the process flow is simple, and it is very suitable for industrial scale-up production.

[0015] 5. Broad application prospects: This method provides a novel green solution for obtaining high-purity squalene from various squalene-rich plant oils, and has great potential for industrial application in the fields of functional oil preparation, deep processing of plant oils, pharmaceuticals, health products and cosmetic raw material production. Attached Figure Description

[0016] Figure 1 Infrared spectra of the ternary supramolecular eutectic solvent and its raw materials prepared in Example 1; Figure 2 This is a comparison of the high-performance liquid chromatography (HPLC) of the squalene product extracted in Example 1 and the raw material macadamia nut oil. Figure 3 The graph shows the effect of recycling the ternary supramolecular eutectic solvent five times on the squalene extraction rate. Detailed Implementation

[0017] The present invention will be further described below with reference to embodiments, but this is not intended to limit the present invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0018] The ternary supramolecular eutectic solvent described in this invention is composed of hydrogen bond acceptors, hydrogen bond donors, and silver salts.

[0019] The molar ratio of the hydrogen bond acceptor, hydrogen bond donor and silver salt is 1:(10~50):(0.5~2).

[0020] The hydrogen bond acceptor is cyclodextrin or its derivative.

[0021] The hydrogen bond acceptor is α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, methylcyclodextrin, hydroxypropylcyclodextrin, or sulfobutylcyclodextrin.

[0022] The hydrogen bond donors are polyols, organic acids, fatty alcohols, or amino acid compounds.

[0023] The hydrogen bond donors are glycerol, propylene glycol, ethylene glycol, lactic acid, citric acid, malic acid, hexanol, octanol, decanol, glycine, alanine, or lysine.

[0024] The silver salt is silver nitrate, silver perchlorate, silver fluoride, or silver sulfate.

[0025] The method for preparing the ternary supramolecular eutectic solvent of the present invention involves mixing hydrogen bond acceptors, hydrogen bond donors and silver salts in the specified proportions and then homogenizing the mixture.

[0026] The homogenization process includes at least one of vortexing, heating, and stirring. The heating temperature is 25~80℃, and the heating time is 0.5~3 hours. An appropriate amount of water (e.g., 5-20 wt.%) may be added during the preparation process to promote homogeneous phase formation.

[0027] The application of the ternary supramolecular eutectic solvent described in this invention is its application in the method of extracting squalene from vegetable oils.

[0028] The method for extracting squalene from vegetable oils includes steps such as extraction system construction, assisted enhanced extraction, and phase separation and product acquisition, specifically including: A. Construction of extraction system: The vegetable oil was mixed evenly with the ternary supramolecular eutectic solvent to obtain extraction system a; B. Enhanced extraction with auxiliary conditions: Extraction system a is carried out under enhanced conditions to obtain extracted system b; C. Phase separation and product acquisition: The extracted system b was subjected to phase separation, and the ternary eutectic solvent phase rich in squalene was collected. The squalene product was obtained by back-extraction.

[0029] The vegetable oils include, but are not limited to, camellia oil, walnut oil, macadamia oil, rapeseed oil, and olive oil. The mass ratio of the vegetable oil to the ternary supramolecular eutectic solvent is 1:0.5 to 1:20.

[0030] The auxiliary enhancement conditions are selected from at least one of ultrasound, stirring, high-speed shearing, microwave or high-pressure treatment, with an extraction temperature of 10~60℃ and an extraction time of 0.05~2 hours.

[0031] The back-extraction agent used in the back-extraction process is selected from at least one of ester (such as ethyl acetate) and alkane (such as n-hexane) organic solvents; the ternary supramolecular eutectic solvent after back-extraction is recovered and reused for the next squalene extraction, thereby realizing the recycling of the solvent.

[0032] The invention will be further illustrated below with specific implementation examples: Example

[0033] (1) Preparation of ternary supramolecular eutectic solvent Weigh sulfobutyl-β-cyclodextrin, ethylene glycol and silver nitrate in a molar ratio of 1:30:1, add 15 wt.% of distilled water, vortex mix at 25°C for 30 seconds, and then heat in a 50°C water bath for 1 hour to form a homogeneous and transparent ternary supramolecular eutectic solvent.

[0034] Through infrared spectroscopy ( Figure 1 Characterization revealed that the infrared spectrum of the ternary supramolecular eutectic solvent showed characteristic absorption peaks for sulfobutyl-cyclodextrin and ethylene glycol, verifying that the chemical structures of these two components remained intact during the formation of the eutectic solvent. Furthermore, the initial peak at 3435 cm⁻¹... -1 The -OH stretching vibration band within the range redshifts to 3307 cm⁻¹. -1 The lower wavenumber region indicates that a strong hydrogen bond network was formed between the hydrogen bond acceptor (cyclodextrin) and the hydrogen bond donor (ethylene glycol) during the formation of the eutectic solvent, confirming the successful preparation of the supramolecular eutectic solvent.

[0035] (2) Extraction of squalene from vegetable oil Weigh 1.0 g of macadamia nut oil and 0.5 g of ternary supramolecular eutectic solvent into a 10 mL centrifuge tube, and vortex for 30 seconds to ensure sufficient contact between the two phases. Then, place the mixture in a high-speed shear apparatus and shear at 10,000 rpm for 3 minutes at 25°C. After treatment, centrifuge the tube at 5,000 rpm for 10 minutes. The system clearly separates into layers, and the lower layer of ternary supramolecular eutectic solvent (rich in squalene) is collected. Add 100 μL of ethyl acetate as a back-extraction agent to the collected ternary supramolecular eutectic solvent phase, vortex for 30 seconds, and allow to stand for separation. Collect the upper ethyl acetate phase. Analyze the purity and content of squalene using high-performance liquid chromatography (HPLC). The squalene extraction rate is 96%, and the purity is higher than 98%. Figure 2 ).

[0036] Examples 2-9 Following the basic method of Example 1, the composition of the ternary supramolecular eutectic solvent, the type of feed oil, or the extraction assistance method were changed. The specific conditions and results are summarized in Table 1 below. Table 1 Extraction conditions and results of different embodiments (CD represents cyclodextrin) Example hydrogen bond acceptor hydrogen bond donor Silver salt vegetable oil Assistance Extraction rate Example 1 Sulfobutyl-β-CD Ethylene glycol silver nitrate Macadamia nut oil High-speed shearing 96% Example 2 Sulfobutyl-β-CD lactic acid silver nitrate Macadamia nut oil High-speed shearing 81% Example 3 Sulfobutyl-β-CD ethanol silver nitrate Macadamia nut oil High-speed shearing 66% Example 4 β-CD Ethylene glycol silver nitrate Macadamia nut oil High-speed shearing 81% Example 5 γ-CD Ethylene glycol silver nitrate Macadamia nut oil High-speed shearing 52% Example 6 Sulfobutyl-β-CD Ethylene glycol silver sulfate Macadamia nut oil High-speed shearing 88% Example 7 Sulfobutyl-β-CD Ethylene glycol silver nitrate Camellia oil High-speed shearing 95% Example 8 Sulfobutyl-β-CD Ethylene glycol silver nitrate olive oil High-speed shearing 96% Example 9 Sulfobutyl-β-CD Ethylene glycol silver nitrate Macadamia nut oil ultrasound 51% Comparative Example 1: The extraction procedure for squalene from vegetable oil was the same as in Example 1, except that the ternary supramolecular eutectic solvent was replaced with water. The extraction rate of squalene was 1.1%.

[0037] Comparative Example 2: The extraction procedure for squalene from vegetable oil was the same as in Example 1, except that the ternary supramolecular eutectic solvent was replaced with ethanol. The extraction rate of squalene was 3.5%.

[0038] Comparative Example 3: The procedure for extracting squalene from vegetable oil was the same as in Example 1, except that the ternary supramolecular eutectic solvent was replaced with... β -Cyclodextrin aqueous solution (5.0 wt.%). Squalene extraction rate: 15%.

[0039] Comparative Example 4: The procedure for extracting squalene from vegetable oil was the same as in Example 1, except that the ternary supramolecular eutectic solvent was replaced with an aqueous solution of silver nitrate (5.0 wt.%). The squalene extraction rate was 21%.

[0040] Comparative Example 5: The extraction procedure for squalene from vegetable oil was the same as in Example 1, except that the ternary supramolecular eutectic solvent was replaced with a traditional eutectic solvent (choline chloride plus glycerol). The squalene extraction rate was 3.4%.

[0041] As can be seen from Table 1 and the comparative results: 1. The ternary supramolecular eutectic solvent provided by this invention (Example 1) achieves an extraction rate of up to 96% for squalene in macadamia nut oil, far exceeding that of single-component solvents such as water, ethanol, cyclodextrin aqueous solution, silver salt aqueous solution, and traditional choline chloride eutectic solvents (Comparative Examples 1-5). This fully demonstrates that the synergistic effect of cyclodextrin inclusion complexation and silver ion coordination is the key to achieving high-efficiency extraction.

[0042] 2. Although the extraction rate changed by changing the hydrogen bond donor (Examples 2 and 3), the type of cyclodextrin (Examples 4 and 5), or the type of silver salt (Example 6), it was still significantly better than the comparative example, indicating that the ternary system described in this invention has certain universality and adjustability.

[0043] 3. The method of the present invention is applicable to a variety of plant oils rich in squalene, such as camellia oil and olive oil (Examples 7 and 8), and the extraction rate is maintained above 95%, showing wide applicability.

[0044] Product purity analysis: The squalene product extracted in Example 1 was analyzed by HPLC, and the results are as follows. Figure 2 As shown, compared to the complex chromatogram of the raw material macadamia nut oil, the chromatogram of the product exhibits a highly sharp and single peak at the squalene elution position, with very few impurity peaks. Area normalization calculations show that the purity of squalene is higher than 98%, demonstrating the excellent selectivity of the method of this invention.

[0045] Solvent recycling performance test: The ternary supramolecular eutectic solvent phase used in Example 1 was back-extracted with ethyl acetate, and the lower layer of the ternary supramolecular eutectic solvent was recovered and directly used in the next round of extraction experiments on fresh macadamia nut oil. This cycle was repeated 5 times, and the extraction rate of squalene was measured each time. The results are as follows: Figure 3 As shown.

[0046] Depend on Figure 3 It is evident that the ternary supramolecular eutectic solvent prepared in this invention exhibits excellent cyclic stability. After five consecutive uses, its extraction rate of squalene from macadamia nut oil only slightly decreased from 96% to approximately 94%, a decrease of about 2%, maintaining extremely high extraction efficiency. This indicates that the solvent has a stable structure, minimal loss of active sites for silver ions and cyclodextrin, and can be reused multiple times, significantly reducing production costs and precious metal consumption, thus possessing potential for industrial application.

[0047] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A ternary supramolecular eutectic solvent, characterized in that, The ternary supramolecular eutectic solvent is composed of hydrogen bond acceptors, hydrogen bond donors, and silver salts.

2. The ternary supramolecular eutectic solvent according to claim 1, characterized in that, The molar ratio of the hydrogen bond acceptor, hydrogen bond donor and silver salt is 1:(10~50):(0.5~2).

3. The ternary supramolecular eutectic solvent according to claim 1 or 2, characterized in that, The hydrogen bond acceptor is cyclodextrin or its derivative.

4. The ternary supramolecular eutectic solvent according to claim 3, characterized in that, The hydrogen bond acceptor is α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, methylcyclodextrin, hydroxypropylcyclodextrin, or sulfobutylcyclodextrin.

5. The ternary supramolecular eutectic solvent according to claim 1 or 2, characterized in that, The hydrogen bond donors are polyols, organic acids, fatty alcohols, or amino acid compounds.

6. The ternary supramolecular eutectic solvent according to claim 5, characterized in that, The hydrogen bond donors are glycerol, propylene glycol, ethylene glycol, lactic acid, citric acid, malic acid, hexanol, octanol, decanol, glycine, alanine, or lysine.

7. The ternary supramolecular eutectic solvent according to claim 1 or 2, characterized in that, The silver salt is silver nitrate, silver perchlorate, silver fluoride, or silver sulfate.

8. A method for preparing a ternary supramolecular eutectic solvent according to any one of claims 1 to 7, characterized in that, It is obtained by mixing hydrogen bond acceptors, hydrogen bond donors and silver salts in the formula and then homogenizing them.

9. An application of the ternary supramolecular eutectic solvent according to any one of claims 1 to 7, characterized in that, The application of the ternary supramolecular eutectic solvent in the extraction of squalene from vegetable oils.

10. The application according to claim 9, characterized in that, The method for extracting squalene from vegetable oils includes steps such as extraction system construction, assisted enhanced extraction, and phase separation and product acquisition, specifically including: A. Construction of extraction system: The vegetable oil was mixed evenly with the ternary supramolecular eutectic solvent to obtain extraction system a; B. Enhanced extraction with auxiliary conditions: Extraction system a is carried out under enhanced conditions to obtain extracted system b; C. Phase separation and product acquisition: The extracted system b was subjected to phase separation, and the ternary eutectic solvent phase rich in squalene was collected. The squalene product was obtained by back-extraction.

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