A method for preparing a liquid phosphatidylcholine

Abstract

The application belongs to the technical field of phospholipids, and discloses a preparation method of liquid phosphatidylcholine. The method is realized by the following steps: taking soybean oil foot as raw material, adding methanol, extracting at low temperature, centrifuging, adding calcium chloride to the separated supernatant to precipitate impurities, stirring, centrifuging again, separating to obtain methanol supernatant rich in phosphatidylcholine calcium salt, adding water and n-hexane to the methanol supernatant after being concentrated to a certain volume, continuously introducing carbon dioxide for calciumization, stirring and extracting, then standing and separating, concentrating the separated upper n-hexane phase to a certain volume, removing the solvent residues through a falling film evaporator, and finally obtaining the product. The application has the following beneficial effects: (1) the application uses soybean oil foot as raw material to extract phosphatidylcholine, which is more economical than soybean powder phospholipid; (2) the phosphatidylcholine prepared by the application is in liquid form, has high fluidity, and the product viscosity is less than or equal to 800 mPa·s; (3) the net extraction rate of the phosphatidylcholine is greater than or equal to 85%, and the product purity is greater than or equal to 50%.

Description

Technical Field

[0001] This invention belongs to the field of phospholipid technology, specifically relating to a method for preparing liquid phosphatidylcholine. Background Technology

[0002] Phosphatidylcholine (PC), a key component of cell membranes, has wide applications in food, pharmaceuticals, and cosmetics. In food, it is a high-quality emulsifier that improves product stability and taste; in pharmaceuticals, it is an important excipient for novel formulations such as liposomes, enhancing drug bioavailability; and in cosmetics, it moisturizes, provides antioxidant benefits, and maintains skin health.

[0003] Currently, phosphatidylcholine is mostly available in powder or granule form, but liquid form has unique advantages and is essential. Liquid phosphatidylcholine is easier to mix with other components, can be quickly and uniformly dispersed in a system, improving production efficiency and product quality stability. In pharmaceutical formulations, the liquid form facilitates direct injection or integration with other drug carriers, reducing processing steps and potential contamination risks.

[0004] However, existing methods for preparing liquid phosphatidylcholine have many limitations, such as low purity, high impurity content, and poor control of oxidation parameters, making it difficult to obtain high-quality liquid phosphatidylcholine. Therefore, developing a method for efficiently preparing high-purity, low-impurity liquid phosphatidylcholine is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing liquid phosphatidylcholine, which can produce high-purity, low-impurity liquid phosphatidylcholine with a high net extraction rate.

[0006] The above-mentioned objective of the present invention is achieved through the following technical means: A method for preparing liquid phosphatidylcholine involves using soybean oil residue as raw material, adding methanol, extracting at low temperature, centrifuging, adding calcium chloride to the separated clear liquid to precipitate impurities, stirring and centrifuging again to separate a methanol clear liquid rich in phosphatidylcholine calcium salt. After the methanol clear liquid is concentrated to a certain volume, water and n-hexane are added, and carbon dioxide is continuously introduced for calcification. The mixture is stirred and extracted, then allowed to stand for separation. The separated upper n-hexane phase is concentrated to a certain volume, and then solvent residue is removed by passing it through a falling film evaporator to finally obtain the product.

[0007] The mass-to-volume ratio of soybean oil residue and methanol in this invention is 1:20 to 1:30 kg / L.

[0008] The separated clear liquid of the present invention is added with calcium chloride, and the mass-to-volume ratio of calcium chloride to methanol is 0.0005:1~0.008:1 kg / L. After stirring, the stirring time for centrifugation is 1~2 hours.

[0009] The low-temperature extraction temperature described in this invention is -10 to -18°C, and the extraction time is 4 to 8 hours.

[0010] The present invention concentrates the methanol solution rich in phosphatidylcholine to a certain volume, with a concentration ratio of 15:1 to 20:1.

[0011] In this invention, the methanol solution rich in phosphatidylcholine is concentrated to a certain volume to obtain a methanol concentrate. Water and n-hexane are then added to the methanol concentrate, with the volume ratio of water to methanol concentrate being 0.8:1 to 1:1 and the volume ratio of n-hexane to methanol concentrate being 2:1 to 2.5:1.

[0012] The carbon dioxide flow rate introduced in this invention is 1.0 L / min to 1.5 L / min, and the extraction time for stirring extraction is 4 to 8 hours.

[0013] The hexane phase described in this invention is concentrated to a certain volume, with a concentration ratio of 3:1 to 6:1.

[0014] In this invention, after concentrating the n-hexane phase to a certain volume, a concentrated n-hexane solution is obtained. This concentrated solution is then passed through a falling film evaporator at a flow rate of 10 L / h to 15 L / h and a temperature of 60 to 65 °C. The vacuum level is -0.08 MPa to -0.09 MPa.

[0015] The phosphatidylcholine prepared by the method of the present invention is in liquid form, with a product purity ≥50%, a net extraction rate of phosphatidylcholine ≥85%, and a viscosity ≤800mPa·s.

[0016] Traditional phosphatidylcholine extraction processes typically use powdered phosphatidylcholine as raw material. The purity of phosphatidylcholine in powdered phosphatidylcholine is 18-26%, and this powdered phosphatidylcholine is a product obtained from soybean oil residue extracted with acetone. This invention directly uses soybean oil residue as raw material. While the purity of phosphatidylcholine in soybean oil residue is 12-18%, lower than that of powdered phosphatidylcholine, it is more price-competitive. Furthermore, this invention targets a liquid product, using oil-rich soybean oil residue as raw material for efficient extraction of phosphatidylcholine and soybean oil. Compared to using soybean powdered phosphatidylcholine to extract high-purity phosphatidylcholine and then adding additional oils to reconstitute it into liquid phosphatidylcholine, this process is simpler and more cost-effective.

[0017] Low-carbon alcohols are the best solvents for extracting phosphatidylcholine from phospholipids. Ethanol is more precise in extracting phosphatidylcholine, but the extraction rate is relatively low. Methanol can completely extract phosphatidylcholine from phospholipids, but it also dissolves more impurities. In order to maximize the extraction of phosphatidylcholine, this invention uses methanol as a solvent.

[0018] The purity of phosphatidylcholine in soybean oil residue is 12-18%, with the remaining components being soybean oil, phospholipid polysaccharides, phosphatidylinositol, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidic acid. At low temperatures, the solubility of phosphatidylinositol, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidic acid in methanol is very low, while the solubility of phosphatidylcholine is less affected by temperature. Using the extraction temperature and solvent ratio used in this invention, the extraction rate of phosphatidylcholine is ≥85%.

[0019] Although low-temperature extraction of phosphatidylcholine yields a high extraction rate, it still dissolves small amounts of phosphatidylinositol, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidic acid, resulting in a phosphatidylcholine purity of less than 50%. This invention adds calcium chloride to calcify the phospholipid components. The calcified phospholipid components have even lower solubility in methanol, while the solubility of calcified phosphatidylcholine is still much higher than that of calcified phosphatidylinositol, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidic acid. Therefore, adding calcium chloride can further improve the purity of phosphatidylcholine.

[0020] Although impurities such as phosphatidylinositol, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidic acid are removed, phosphatidylcholine also forms phosphatidylcholine calcium salt. Therefore, it is necessary to decalcify the phosphatidylcholine calcium salt. This invention uses a hexane-methanol-water three-phase system for decalcification. The solubility of calcium carbonate is much lower than that of phosphatidylcholine calcium salt. Therefore, carbon dioxide is introduced into the three-phase system of phosphatidylcholine calcium salt. The calcium ions in the phosphatidylcholine calcium salt will react with carbon dioxide and water to form calcium carbonate precipitate. After standing and separating, phosphatidylcholine and soybean oil are enriched in the upper hexane phase, while calcium carbonate and phospholipid polysaccharides are distributed in the lower methanol-water phase.

[0021] One of the quality indicators for phospholipids is that the residual hexane should be ≤25mg / kg. Traditional processes use concentrators or vacuum ovens to remove solvent residue. As the volume of the liquid decreases, solids accumulate, presenting two limitations: first, the solvent is compressed within the solids, requiring significant energy and time for removal; second, heat is trapped within the material for an extended period, leading to browning of the phospholipids and an increase in peroxide value. Increased peroxide value can trigger an irreversible chain reaction, significantly shortening the product's shelf life. This invention utilizes a falling film evaporator. The falling film evaporator uses gravity to evenly distribute the liquid on the inner wall of the heating tube, forming a thin film. A vacuum environment lowers the liquid's boiling point, allowing for rapid solvent evaporation at low temperatures, thus completing the concentration. This invention employs a multi-effect falling film evaporator, controlling the flow rate within the specified parameters, enabling top-feed and bottom-product output.

[0022] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: (1) The present invention uses soybean oil residue as raw material to extract phosphatidylcholine, which is cheaper than soybean powder phospholipids.

[0023] (2) The phosphatidylcholine prepared by this invention is in liquid form, has high fluidity, and the product viscosity is ≤800mPa·s; (3) The net extraction rate of phosphatidylcholine of the present invention is ≥85%, and the product purity is ≥50%. Detailed Implementation

[0024] To facilitate understanding of the present invention, a more complete description is provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0025] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0026] Example 1 100 kg of soybean oil residue (phosphatidylcholine content 12.15%) was weighed and added to 2500 L of methanol. Extraction was carried out at -18℃ for 6 h. After centrifugation, 2400 L of clear liquid was obtained. 1.2 kg of calcium chloride was added to the clear liquid, and the mixture was stirred for 2 h. After centrifugation, a methanol clear liquid rich in phosphatidylcholine calcium salts was separated. The methanol clear liquid was concentrated to approximately 150 L to obtain a methanol concentrate. 150 L of water and 300 L of n-hexane were added to the methanol concentrate, and carbon dioxide was continuously introduced at a flux of 1.2 L / min. Extraction was carried out with stirring for 4 h. After standing and separation, the upper n-hexane phase (310 L) was separated. The n-hexane phase was concentrated to approximately 60 L to obtain a n-hexane concentrate. The n-hexane concentrate was then processed using a multi-effect falling film evaporator at a flow rate of 15 L / h, a temperature of 60℃, and a vacuum of -0.085. The final product yielded 20.41 kg of liquid phosphatidylcholine with a purity of 51.2%, a net extraction rate of 86.0%, and a viscosity of 785 mPa·s.

[0027] Example 2 100 kg of soybean oil residue (phosphatidylcholine content 12.15%) was weighed and added to 2000 L of methanol. Extraction was carried out at -10℃ for 4 h. After centrifugation, 1900 L of clear liquid was obtained. 0.95 kg of calcium chloride was added to the clear liquid, and the mixture was stirred for 1 h. After centrifugation, a methanol clear liquid rich in phosphatidylcholine calcium salts was separated. The methanol clear liquid was concentrated to approximately 100 L to obtain a methanol concentrate. 100 L of water and 200 L of n-hexane were added to the methanol concentrate, and carbon dioxide was continuously introduced at a flux of 1.0 L / min. Extraction was carried out with stirring for 4 h. After standing and separation, the upper n-hexane phase (210 L) was separated. The n-hexane phase was concentrated to approximately 70 L to obtain a n-hexane concentrate. The n-hexane concentrate was then processed using a multi-effect falling film evaporator at a flow rate of 10 L / h, a temperature of 65℃, and a vacuum of -0.09 μL. Finally, 20.5 kg of liquid phosphatidylcholine product was obtained with a purity of 50.8%, a net extraction rate of phosphatidylcholine of 85.7%, and a product viscosity of 757 mPa·s.

[0028] Example 3 100 kg of soybean oil residue (phosphatidylcholine content 12.15%) was weighed and added to 2000 L of methanol. Extraction was carried out at -15 °C for 8 h. After centrifugation, 1900 L of clear liquid was obtained. 1.52 kg of calcium chloride was added to the clear liquid, and the mixture was stirred for 1 h. After centrifugation, a methanol clear liquid rich in phosphatidylcholine calcium salts was separated. The methanol clear liquid was concentrated to approximately 120 L to obtain a methanol concentrate. 120 L of water and 250 L of n-hexane were added to the methanol concentrate, and carbon dioxide was continuously introduced at a flux of 1.2 L / min. Extraction was carried out with stirring for 5 h. After standing and separation, the upper n-hexane phase (260 L) was separated. The n-hexane phase was concentrated to approximately 65 L to obtain a n-hexane concentrate. The n-hexane concentrate was then processed using a multi-effect falling film evaporator at a flow rate of 15 L / h, a temperature of 65 °C, and a vacuum of -0.08. The final product yielded 20.56 kg of liquid phosphatidylcholine with a purity of 51.7%, a net extraction rate of 87.5%, and a viscosity of 776 mPa·s.

[0029] Example 4 100 kg of soybean oil residue (phosphatidylcholine content 12.15%) was weighed and added to 3000 L of methanol. Extraction was carried out at -18℃ for 8 h. After centrifugation, 2900 L of clear liquid was obtained. 2.0 kg of calcium chloride was added to the clear liquid, and the mixture was stirred for 1 h. After centrifugation, a methanol clear liquid rich in phosphatidylcholine calcium salts was separated. The methanol clear liquid was concentrated to approximately 150 L to obtain a methanol concentrate. 130 L of water and 300 L of n-hexane were added to the methanol concentrate, and carbon dioxide was continuously introduced at a flux of 1.5 L / min. Extraction was carried out with stirring for 6 h. After standing and separation, the upper n-hexane phase (310 L) was separated. The n-hexane phase was concentrated to approximately 60 L to obtain a n-hexane concentrate. The n-hexane concentrate was then processed using a multi-effect falling film evaporator at a flow rate of 10 L / h, a temperature of 60℃, and a vacuum of -0.08 ppm. The final product yielded 20.08 kg of liquid phosphatidylcholine with a purity of 52.3%, a net extraction rate of 86.4%, and a viscosity of 783 mPa·s.

[0030] Example 5 100 kg of soybean oil residue (phosphatidylcholine content 16.34%) was weighed and added to 2000 L of methanol. Extraction was carried out at -10℃ for 4 h. After centrifugation, 1900 L of clear liquid was obtained. 1.0 kg of calcium chloride was added to the clear liquid, and the mixture was stirred for 1 h. After centrifugation, a methanol clear liquid rich in phosphatidylcholine calcium salts was separated. The methanol clear liquid was concentrated to approximately 100 L to obtain a methanol concentrate. 90 L of water and 200 L of n-hexane were added to the methanol concentrate, and carbon dioxide was continuously introduced at a flux of 1.0 L / min. Extraction was carried out with stirring for 4 h. After standing and separation, the upper n-hexane phase (210 L) was separated. The n-hexane phase was concentrated to approximately 70 L to obtain a n-hexane concentrate. The n-hexane concentrate was then processed using a multi-effect falling film evaporator at a flow rate of 12 L / h, a temperature of 63℃, and a vacuum of -0.09. The final product yielded 28.54 kg of liquid phosphatidylcholine with a purity of 50.5%, a net extraction rate of 88.2%, and a viscosity of 752 mPa·s.

[0031] Example 6 100 kg of soybean oil residue (phosphatidylcholine content 16.34%) was weighed and added to 3000 L of methanol. Extraction was carried out at -15 °C for 6 h. After centrifugation, 2900 L of clear liquid was obtained. 1.75 kg of calcium chloride was added to the clear liquid, and the mixture was stirred for 2 h. After centrifugation, a methanol-rich clear liquid containing calcium phosphatidylcholine salts was separated. The methanol clear liquid was concentrated to approximately 180 L to obtain a methanol concentrate. 180 L of water and 400 L of n-hexane were added to the methanol concentrate, and carbon dioxide was continuously introduced at a flux of 1.5 L / min. Extraction was carried out with stirring for 5 h. After standing and separation, the upper n-hexane phase (410 L) was separated. The n-hexane phase was concentrated to approximately 70 L to obtain a n-hexane concentrate. The n-hexane concentrate was then processed using a multi-effect falling film evaporator at a flow rate of 15 L / h, a temperature of 65 °C, and a vacuum of -0.09 μL. The final yield was 27.22 kg of liquid phosphatidylcholine product with a purity of 51.2%, a net extraction rate of 85.3%, and a product viscosity of 766 mPa·s.

[0032] Example 7 100 kg of soybean oil residue (phosphatidylcholine content 13.16%) was weighed and added to 3000 L of methanol. Extraction was carried out at -18℃ for 8 h. After centrifugation, 2900 L of clear liquid was obtained. 2.3 kg of calcium chloride was added to the clear liquid, and the mixture was stirred for 1 h. After centrifugation, a methanol clear liquid rich in phosphatidylcholine calcium salts was separated. The methanol clear liquid was concentrated to approximately 175 L to obtain a methanol concentrate. 170 L of water and 350 L of n-hexane were added to the methanol concentrate, and carbon dioxide was continuously introduced at a flux of 1.5 L / min. Extraction was carried out with stirring for 6 h. After standing and separation, the upper n-hexane phase (360 L) was separated. The n-hexane phase was concentrated to approximately 60 L to obtain a n-hexane concentrate. The n-hexane concentrate was then processed using a multi-effect falling film evaporator at a flow rate of 10 L / h, a temperature of 65℃, and a vacuum of -0.085. The final product yielded 22.14 kg of liquid phosphatidylcholine with a purity of 52.0%, a net extraction rate of 87.5%, and a viscosity of 768 mPa·s.

[0033] Example 8 100 kg of soybean oil residue (phosphatidylcholine content 13.16%) was weighed and added to 2000 L of methanol. Extraction was carried out at -15 °C for 4 h. After centrifugation, 1900 L of clear liquid was obtained. 1.3 kg of calcium chloride was added to the clear liquid, and the mixture was stirred for 1 h. After centrifugation, a methanol clear liquid rich in phosphatidylcholine calcium salts was separated. The methanol clear liquid was concentrated to approximately 100 L to obtain a methanol concentrate. 100 L of water and 200 L of n-hexane were added to the methanol concentrate, and carbon dioxide was continuously introduced at a flux of 1.2 L / min. Extraction was carried out with stirring for 4 h. After standing and separation, the upper n-hexane phase (210 L) was separated. The n-hexane phase was concentrated to approximately 50 L to obtain a n-hexane concentrate. The n-hexane concentrate was then processed using a multi-effect falling film evaporator at a flow rate of 15 L / h, a temperature of 65 °C, and a vacuum of -0.08. The final product yielded 22.03 kg of liquid phosphatidylcholine with a purity of 51.6%, a net extraction rate of 86.4%, and a viscosity of 773 mPa·s.

[0034] Example 9 100 kg of soybean oil residue (phosphatidylcholine content 17.24%) was weighed and added to 2000 L of methanol. Extraction was carried out at -10℃ for 4 h. After centrifugation, 1900 L of clear liquid was obtained. 0.95 kg of calcium chloride was added to the clear liquid, and the mixture was stirred for 2 h. After centrifugation, a methanol-rich clear liquid containing calcium phosphatidylcholine salts was separated. The methanol clear liquid was concentrated to approximately 120 L to obtain a methanol concentrate. 120 L of water and 250 L of n-hexane were added to the methanol concentrate, and carbon dioxide was continuously introduced at a flux of 1.0 L / min. Extraction was carried out with stirring for 4 h. After standing and separation, the upper n-hexane phase (260 L) was separated. The n-hexane phase was concentrated to approximately 50 L to obtain a n-hexane concentrate. The n-hexane concentrate was then processed using a multi-effect falling film evaporator at a flow rate of 10 L / h, a temperature of 60℃, and a vacuum of -0.09 μL. The final product yielded 29.35 kg of liquid phosphatidylcholine with a purity of 50.7%, a net extraction rate of 86.3%, and a viscosity of 780 mPa·s.

[0035] Example 10 100 kg of soybean oil residue (phosphatidylcholine content 17.24%) was weighed and added to 2500 L of methanol. Extraction was carried out at -18℃ for 6 h. After centrifugation, 2400 L of clear liquid was obtained. 1.9 kg of calcium chloride was added to the clear liquid, and the mixture was stirred for 2 h. After centrifugation, a methanol clear liquid rich in phosphatidylcholine calcium salts was separated. The methanol clear liquid was concentrated to approximately 120 L to obtain a methanol concentrate. 120 L of water and 250 L of n-hexane were added to the methanol concentrate, and carbon dioxide was continuously introduced at a flux of 1.2 L / min. Extraction was carried out with stirring for 6 h. After standing and separation, 260 L of the upper n-hexane phase was separated. The n-hexane phase was concentrated to approximately 50 L to obtain a n-hexane concentrate. The n-hexane concentrate was then processed using a multi-effect falling film evaporator at a flow rate of 10 L / h, a temperature of 65℃, and a vacuum of -0.09. The final product yielded 28.65 kg of liquid phosphatidylcholine with a purity of 52.7%, a net extraction rate of 87.6%, and a viscosity of 755 mPa·s.

[0036] The data from Examples 1 to 10 are summarized in Table 1 (as shown below): Table 1 Production Data of Examples 1 to 10 Example 1 12.15 100 51.2 20.41 86.0 785 Example 2 12.15 100 50.8 20.50 85.7 757 Example 3 12.15 100 51.7 20.56 87.5 776 Example 4 12.15 100 52.3 20.08 86.4 783 Example 5 16.34 100 50.5 28.54 88.2 752 Example 6 16.34 100 51.2 27.22 85.3 766 Example 7 13.16 100 52 22.14 87.5 768 Example 8 13.16 100 51.6 22.03 86.4 773 Example 9 17.24 100 50.7 29.35 86.3 780 Example 10 17.24 100 52.7 28.65 87.6 755 Note: Net extraction rate of phosphatidylcholine (%) = (product purity × product weight) × 100% ÷ (raw material purity × raw material weight).

[0037] As can be seen from the summary results in Table 1, the purity of the products in the 10 examples ranged from 50.7% to 52.7%, all ≥50%; the net extraction rate of phosphatidylcholine ranged from 85.3% to 88.2%, all ≥85%; and the product viscosity ranged from 752% to 785 mPa·s, all ≤800 mPa·s.

[0038] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing liquid phosphatidylcholine, characterized in that, Using soybean oil residue as raw material, methanol is added, and the mixture is extracted at low temperature. After centrifugation, calcium chloride is added to the separated clear liquid to precipitate impurities. After stirring, the mixture is centrifuged again to separate a methanol clear liquid rich in phosphatidylcholine calcium salt. After the methanol clear liquid is concentrated to a certain volume, water and n-hexane are added, and carbon dioxide is continuously purged for calcification. The mixture is stirred and extracted, and then allowed to stand for separation. The upper n-hexane phase is concentrated to a certain volume and then the solvent residue is removed by a falling film evaporator to finally obtain the product.

2. The method for preparing liquid phosphatidylcholine according to claim 1, characterized in that, The mass-to-volume ratio of soybean oil residue to methanol is 1:20 to 1:30 kg / L.

3. The method for preparing liquid phosphatidylcholine according to claim 1, characterized in that, The separated clear liquid was added with calcium chloride, and the mass-to-volume ratio of calcium chloride to methanol was 0.0005:1 to 0.008:1 kg / L. After stirring, the mixture was centrifuged again for 1 to 2 hours.

4. The method for preparing liquid phosphatidylcholine according to claim 1, characterized in that, The low-temperature extraction temperature is -10~-18℃, and the extraction time is 4~8h.

5. The method for preparing liquid phosphatidylcholine according to claim 1, characterized in that, The methanol solution rich in phosphatidylcholine was concentrated to a certain volume, with a concentration ratio of 15:1 to 20:

1.

6. The method for preparing liquid phosphatidylcholine according to claim 1, characterized in that, After concentrating the phosphatidylcholine-rich methanol solution to a certain volume, a methanol concentrate is obtained. Water and n-hexane are then added to the methanol concentrate, with the volume ratio of water to methanol concentrate being 0.8:1 to 1:1 and the volume ratio of n-hexane to methanol concentrate being 2:1 to 2.5:

1.

7. The method for preparing liquid phosphatidylcholine according to claim 1, characterized in that, The carbon dioxide flow rate is 1.0 L / min to 1.5 L / min, and the extraction time for stirring extraction is 4 to 8 hours.

8. The method for preparing liquid phosphatidylcholine according to claim 1, characterized in that, The n-hexane phase is concentrated to a certain volume, with a concentration ratio of 3:1 to 6:

1.

9. A method for preparing liquid phosphatidylcholine according to claim 1, characterized in that, After concentrating the n-hexane phase to a certain volume, a n-hexane concentrate is obtained. The n-hexane concentrate is then passed through a falling film evaporator at a flow rate of 10 L / h to 15 L / h, a temperature of 60 to 65 °C, and a vacuum degree of -0.08 MPa to -0.09 MPa.

10. The method for preparing liquid phosphatidylcholine according to claim 1, characterized in that, The phosphatidylcholine obtained by the preparation method is in liquid form, with a product purity ≥50%, a net extraction rate of phosphatidylcholine ≥85%, and a viscosity ≤800mPa·s.