Method for synthesizing hydrogenated lecithin by using micro-fixed bed liquid phase continuous hydrogenation

Abstract

The invention provides a method for synthesizing hydrogenated lecithin by using micro-fixed bed liquid-phase continuous hydrogenation, which specifically comprises the following steps: introducing a soybean phospholipid solution and hydrogen into a hydrogenation reaction column for reaction to obtain a hydrogenated lecithin crude product solution, and then concentrating and removing a solvent from the hydrogenated lecithin crude product solution to obtain the hydrogenated lecithin. The hydrogenation reaction column is internally provided with the catalyst bed layer, and the catalyst bed layer is sequentially filled with the lower-layer microporous catalyst and the upper-layer macroporous catalyst from bottom to top, so that a'rapid conversion-deep hydrogenation 'graded reaction system can be formed, and the overall reaction efficiency and the product purity can be improved; the method is safe, efficient, simple and convenient to operate, low in catalyst dosage, capable of replacing a traditional kettle type hydrogenation method and suitable for being applied to industrial large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and particularly relates to a method for continuously synthesizing hydrogenated lecithin by micro-fixed bed liquid-phase hydrogenation. Background Art

[0002] Hydrogenated lecithin is an important raw material for organic chemical industry intermediates obtained by catalytic hydrogenation of lecithin, and is widely used in fine chemical industries such as medicine and cosmetics. At present, the synthesis of hydrogenated lecithin mainly uses egg yolk lecithin or soybean lecithin as raw materials, and uses catalytic hydrogenation reaction to reduce its double bonds. This process has high atom economy and low pollution, and is a green and environmental protection process. At present, the process of producing hydrogenated lecithin by catalytic hydrogenation reduction is mainly in batch autoclaves. Batch production operation is cumbersome, and the mass transfer efficiency between gas, liquid and solid phases is low, which makes the total reaction time long, production efficiency low, and catalyst dosage large. More importantly, some processes such as catalyst feeding and discharging filtration operations and the reaction conditions of large volume and high pressure make the process have greater safety risks. Chinese patents CN111116643A, CN112142777A, and CN113105501A all reported the process of preparing hydrogenated soybean lecithin by autoclave hydrogenation, using methanol, ethanol, isopropanol, n-hexane or their mixtures as solvents, using palladium-carbon, Raney nickel or their mixtures as catalysts, reaction pressure 0.8-2 Mpa, temperature 30-68 °C, catalyst dosage up to 1%-10% of the substrate weight, and reaction time about 1-3 hours. Although the article (International Food Research Journal, 2014, 21, 1061-1065) discloses a new continuous method for synthesizing hydrogenated lecithin by continuous hydrogenation of soybean phospholipids, using 10% palladium / carbon as the catalyst and n-hexane as the solvent, at 60 °C and 20 bar pressure, but this process coats the catalyst on the reactor wall, and the mass transfer effect has not been essentially improved. The article does not also introduce key information such as product conversion rate and catalyst life in detail. At the same time, there are technical problems such as the difficulty in manufacturing the catalyst column on a large scale and the difficulty in scaling up the production of hydrogenated lecithin. In addition, the fatty acid chains in soybean phospholipids usually contain multiple unsaturated double bonds. In the hydrogenation reaction, hydrogen dissociates into active hydrogen atoms on the surface of the catalyst and is gradually added to the double bonds. Inevitably, some incompletely hydrogenated phospholipid intermediates will be produced during this process, affecting the purity and yield of the product. Therefore, it is urgent to research and transform the process by using new intrinsically safe technologies to overcome the problems of high cost, low efficiency, high pollution and safety risks of the existing process. Summary of the Invention

[0003] Technical problem to be solved: Aiming at the above problems existing in the prior art, the technical problem to be solved by the present invention is to provide a method for continuously synthesizing hydrogenated lecithin by micro-fixed bed liquid phase hydrogenation, which is used to solve the problems of large catalyst consumption, low production efficiency and high safety risks in the process of synthesizing hydrogenated lecithin.

[0004] Technical solution: A method for continuously synthesizing hydrogenated lecithin by micro-fixed bed liquid phase hydrogenation. Introduce soybean phospholipid solution and hydrogen into a hydrogenation reaction column for reaction to obtain a crude hydrogenated lecithin solution, and then concentrate and remove the solvent from the crude hydrogenated lecithin solution to obtain hydrogenated lecithin. Among them, a catalyst bed layer is provided in the hydrogenation reaction column. The catalyst bed layer is filled with a lower-layer microporous catalyst and an upper-layer macroporous catalyst in sequence from bottom to top, with a volume ratio of 1:(2 - 3), and an inert ceramic fiber separation layer is contained in the middle. Further, the carrier of the lower-layer microporous catalyst is SiO2, and transition metal Ni is loaded on the carrier, with a pore diameter of 4 - 7nm; the carrier of the upper-layer macroporous catalyst is alumina, and active metal is loaded on the carrier, with a pore diameter of 32 - 38nm. Further, the preparation steps of the lower-layer microporous catalyst are as follows: S1. Dissolve ethylene oxide in 1mol / L nitric acid, then add tetraethyl orthosilicate, seal and stir at room temperature for 30 - 40min, dry at 40℃ for 2 - 3 days, cut the obtained white gel into small pieces, wash with water and ammonia water in sequence, then wash with water again until neutral, dry at 40℃ for 20 - 24h, continue to dry at 100 - 110℃ for 6 - 12h, and calcine at 500 - 600℃ for 10 - 12h to obtain the carrier SiO2. S2. Immerse the carrier SiO2 in a 0.3 - 0.4mg / mL Ni(NO3)2·6H2O solution, with a mass-volume ratio of 8mg:(1 - 3)mL, stir evenly, dry overnight to obtain a solid powder, and calcine at 500 - 550℃ for 3 - 4h to obtain the lower-layer microporous catalyst Ni / SiO2. Further, in step S1, the mass-volume ratio of ethylene oxide, tetraethyl orthosilicate and nitric acid is 1g:(6 - 7)g:(8 - 9)mL. Further, the preparation steps of the upper-layer macroporous catalyst are as follows: S1. Prepare an active metal salt solution with a concentration of 1 - 2mol / L. S2. Thoroughly rinse alumina with deionized water, dry it, calcine it at 400 - 600℃ for 2 - 4h, cool it to room temperature, and place it in a constant temperature drying oven for activation to obtain activated alumina. S3. The activated alumina is immersed in the active metal salt solution by the equal-volume impregnation method, ultrasonically assisted for 30 - 60 min, allowed to stand for 12 h, then dried at 100 - 110 °C for 5 - 6 h, and calcined at 300 - 350 °C for 2 - 3 h to obtain the upper macroporous catalyst with active metal supported on alumina. Further, the active metal is one or more of palladium, platinum, and ruthenium; the loading amount of the active metal is 0.5 - 10%. Further, it specifically includes the following steps: 1) Load the catalyst into the hydrogenation reaction column, and purge it with nitrogen during the loading process; 2) Dissolve the soy lecithin in a solvent to obtain a soy lecithin solution; 3) Regulate the reaction temperature in the hydrogenation reaction column through a temperature control device, and regulate the reaction pressure in the hydrogenation reaction column through a pressure regulating device; 4) First, pass the soy lecithin solution and hydrogen together through the gas-liquid distributor at the inlet of the hydrogenation reaction column, disperse them evenly, and then enter the hydrogenation reaction column to uniformly contact the catalyst bed cross-section to occur hydrogenation reaction. This process maintains continuous feeding; 5) After the hydrogenation reaction is completed, collect the flowing reaction solution, which is the crude hydrogenated lecithin solution; 6) Concentrate the crude hydrogenated lecithin solution to remove the solvent to obtain hydrogenated lecithin; 7) After the reaction ends, stop feeding, wash the catalyst bed with the same solvent as in step 2), then blow dry the washed catalyst bed with nitrogen, and under the nitrogen purging state, lead out the reacted catalyst from the hydrogenation reaction column and collect it in water. Further, in step 2), the mass-volume ratio of soy lecithin to the solvent is 1 g:(5 - 30) mL; the solvent is any one of tetrahydrofuran, dichloromethane, ethanol, and n-hexane. Further, in step 3), the reaction temperature is 30 - 80 °C, and the reaction pressure is 1 - 5 Mpa. Further, in step 4), the flow rate of the soy lecithin solution is 0.02 - 0.2 mL / min; the flow rate of the hydrogen is 20 - 40 mL / min. Beneficial effects: 1. Different from the batch hydrogenation process that frequently inputs powdered catalysts and filters dangerous waste catalysts, the present invention uses a micro-fixed bed liquid-phase continuous hydrogenation to synthesize hydrogenated lecithin. The hydrogenation catalyst has extremely low danger during the loading and unloading processes, and the operation frequency is lower. The reactor has a small volume, less on-line material volume, and higher safety, meeting the safety transformation requirements of the state for high-risk processes in the fine chemical industry; in addition, the soy lecithin solution can fully contact with hydrogen and the solid catalyst, and compared with batch hydrogenation, the reaction rate is greatly increased. This continuous production process is more convenient to operate and more efficient in production; 2. In the hydrogenation reaction column of the present invention, a catalyst bed layer is provided. The catalyst bed layer is filled with a lower-layer microporous catalyst and an upper-layer macroporous catalyst in sequence from bottom to top. The upper layer quickly completes the main reaction, and the lower layer focuses on converting intermediates, forming a hierarchical reaction system of "rapid conversion - deep hydrogenation", which is beneficial to improving the overall reaction efficiency and product purity. In addition, there is an inert ceramic fiber separation layer between the lower-layer microporous catalyst and the upper-layer macroporous catalyst, which is mainly used to prevent the mixing of two catalysts with different pore sizes due to the impact of gravity or hydrogen gas flow rate. Mixing may cause wear of the catalyst or the reactant soy lecithin may not be able to achieve stepwise reactions according to the designed path. Macromolecules may prematurely contact the microporous catalyst, resulting in pore blockage and reducing the overall conversion rate. 3. The upper-layer macroporous catalyst prepared in the present invention uses alumina as a carrier and is loaded with active metals. The macroporous structure and large surface area of the catalyst can enable the reactant soy lecithin and hydrogen to quickly diffuse to the active sites, avoiding mass transfer limitations. The active metals palladium, platinum, and ruthenium have extremely high catalytic activity for the hydrogenation reaction, achieving preliminary high-efficiency hydrogenation. The lower-layer microporous catalyst uses SiO2 as a carrier and is loaded with transition metal Ni. The microporous structure of the catalyst prolongs the residence time of the intermediate (partially saturated phospholipid) in the catalyst, which is beneficial to promoting the full contact between the intermediate and hydrogen, ensuring the full progress of the reaction. The loaded transition metal Ni is more selective, providing rich active sites to hydrogenate the remaining unsaturated bonds to a greater extent, reducing the generation of incompletely hydrogenated intermediates, and improving the product purity. Specific embodiments The present invention will be further described below in conjunction with embodiments. The following embodiments are explanations of the present invention, and the present invention is not limited to the following embodiments: In the hydrogenation reaction column of the present invention, a catalyst bed layer is provided. The catalyst bed layer is filled with a lower-layer microporous catalyst and an upper-layer macroporous catalyst in sequence from bottom to top. The upper layer quickly completes the main reaction, and the lower layer focuses on converting intermediates, forming a hierarchical reaction system of "rapid conversion - deep hydrogenation", which is beneficial to improving the overall reaction efficiency and product purity. The upper-layer macroporous catalyst prepared in the present invention uses alumina as a carrier and is loaded with active metals, with a pore size of 4 - 7 nm. The macroporous structure and large surface area can enable the reactant soy lecithin and hydrogen to quickly diffuse to the active sites, avoiding mass transfer limitations. The active metals palladium, platinum, and ruthenium have extremely high catalytic activity for the hydrogenation reaction, achieving preliminary high-efficiency hydrogenation. The lower-layer microporous catalyst of the present invention uses SiO2 as a carrier and is loaded with transition metal Ni, with a pore size of 32 - 38 nm. The microporous structure prolongs the residence time of the intermediate (partially saturated phospholipid) in the catalyst, which is beneficial to promoting the full contact between the intermediate and hydrogen, ensuring the full progress of the reaction. The loaded transition metal Ni is more selective, providing rich active sites to completely hydrogenate the remaining unsaturated bonds, reducing the generation of incompletely hydrogenated intermediates, and improving the product purity. Example 1 The preparation steps of the lower - layer microporous catalyst are as follows: S1. Dissolve 10 g of ethylene oxide in 90 mL of 1 mol / L nitric acid, then add 60 g of tetraethyl orthosilicate. After sealing and stirring at room temperature for 30 min, dry at 40 °C for 2 days. Cut the obtained white gel into small pieces, wash them successively with water and ammonia water, then wash with water again until neutral. After drying at 40 °C for 20 h, continue to dry at 110 °C for 8 h and calcine at 550 °C for 12 h to obtain the carrier SiO₂; S2. Immerse 800 mg of the carrier SiO₂ in 100 mL of 0.3 mg / mL Ni(NO₃)₂·6H₂O solution, stir evenly, dry overnight to obtain a solid powder, and calcine at 550 °C for 4 h to obtain the lower - layer microporous catalyst Ni / SiO₂. Example 2 The preparation steps of the lower - layer microporous catalyst are as follows: S1. Dissolve 10 mg of ethylene oxide in 90 mL of 1 mol / L nitric acid, then add 60 mg of tetraethyl orthosilicate. After sealing and stirring at room temperature for 30 min, dry at 40 °C for 2 days. Cut the obtained white gel into small pieces, wash them successively with water and ammonia water, then wash with water again until neutral. After drying at 40 °C for 20 h, continue to dry at 110 °C for 8 h and calcine at 550 °C for 12 h to obtain the carrier SiO₂; S2. Immerse 800 mg of the carrier SiO₂ in 200 mL of 0.3 mg / mL Ni(NO₃)₂·6H₂O solution, stir evenly, dry overnight to obtain a solid powder, and calcine at 550 °C for 4 h to obtain the lower - layer microporous catalyst Ni / SiO₂. Example 3 The preparation steps of the lower - layer microporous catalyst are as follows: S1. Dissolve 10 mg of ethylene oxide in 90 mL of 1 mol / L nitric acid, then add 60 mg of tetraethyl orthosilicate. After sealing and stirring at room temperature for 30 min, dry at 40 °C for 2 days. Cut the obtained white gel into small pieces, wash them successively with water and ammonia water, then wash with water again until neutral. After drying at 40 °C for 20 h, continue to dry at 110 °C for 8 h and calcine at 550 °C for 12 h to obtain the carrier SiO₂; S2. Immerse 800 mg of the carrier SiO₂ in 300 mL of 0.3 mg / mL Ni(NO₃)₂·6H₂O solution, stir evenly, dry overnight to obtain a solid powder, and calcine at 550 °C for 4 h to obtain the lower - layer microporous catalyst Ni / SiO₂. Example 4 The preparation steps of the lower - layer microporous catalyst are as follows: S1. Dissolve 10 mg of ethylene oxide in 90 mL of 1 mol / L nitric acid, then add 60 mg of tetraethyl orthosilicate. After sealing and stirring at room temperature for 30 min, dry at 40 °C for 2 days. Cut the obtained white gel into small pieces, wash them successively with water and ammonia water, and then wash with water again until neutral. After drying at 40 °C for 20 h, continue to dry at 110 °C for 8 h and calcine at 500 °C for 12 h to obtain the carrier SiO2; S2. Immerse 800 mg of the carrier SiO2 in 200 mL of 0.3 mg / mL Ni(NO3)2·6H2O solution, stir evenly, dry overnight to obtain a solid powder, and calcine at 550 °C for 4 h to obtain the lower-layer microporous catalyst Ni / SiO2. Example 5 The preparation steps of the lower-layer microporous catalyst are as follows: S1. Dissolve 10 mg of ethylene oxide in 90 mL of 1 mol / L nitric acid, then add 60 mg of tetraethyl orthosilicate. After sealing and stirring at room temperature for 30 min, dry at 40 °C for 2 days. Cut the obtained white gel into small pieces, wash them successively with water and ammonia water, and then wash with water again until neutral. After drying at 40 °C for 20 h, continue to dry at 110 °C for 8 h and calcine at 600 °C for 12 h to obtain the carrier SiO2; S2. Immerse 800 mg of the carrier SiO2 in 200 mL of 0.3 mg / mL Ni(NO3)2·6H2O solution, stir evenly, dry overnight to obtain a solid powder, and calcine at 550 °C for 4 h to obtain the lower-layer microporous catalyst Ni / SiO2. Comparative Example 1 The difference between this comparative example and Example 2 is that the mass-to-volume ratio of the carrier SiO2 to the Ni(NO3)2·6H2O solution is too low, which is 8 mg:0.5 mL, and the details are as follows: The preparation steps of the lower-layer microporous catalyst are as follows: S1. Dissolve 10 mg of ethylene oxide in 90 mL of 1 mol / L nitric acid, then add 60 mg of tetraethyl orthosilicate. After sealing and stirring at room temperature for 30 min, dry at 40 °C for 2 days. Cut the obtained white gel into small pieces, wash them successively with water and ammonia water, and then wash with water again until neutral. After drying at 40 °C for 20 h, continue to dry at 110 °C for 8 h and calcine at 550 °C for 12 h to obtain the carrier SiO2; S2. Immerse 800 mg of the carrier SiO2 in 50 mL of 0.3 mg / mL Ni(NO3)2·6H2O solution, stir evenly, dry overnight to obtain a solid powder, and calcine at 550 °C for 4 h to obtain the lower-layer microporous catalyst Ni / SiO2. Comparative Example 2 The difference between this comparative example and Example 2 is that the mass-to-volume ratio of the carrier SiO2 to the Ni(NO3)2·6H2O solution is too high, which is 8 mg:4 mL, and the details are as follows: The preparation steps of the lower-layer microporous catalyst are as follows: S1. Dissolve 10 mg of ethylene oxide in 90 mL of 1 mol / L nitric acid, then add 60 mg of tetraethyl orthosilicate. After sealing and stirring at room temperature for 30 min, dry at 40 °C for 2 days. Cut the obtained white gel into small pieces, wash them successively with water and ammonia water, and then wash with water again until neutral. After drying at 40 °C for 20 h, continue to dry at 110 °C for 8 h and calcine at 550 °C for 12 h to obtain the support SiO2; S2. Immerse 800 mg of the support SiO2 in 400 mL of 0.3 mg / mL Ni(NO3)2·6H2O solution, stir evenly, dry overnight to obtain a solid powder, and calcine at 550 °C for 4 h to obtain the lower-layer microporous catalyst Ni / SiO2. Comparative Example 3 The difference between this comparative example and Example 2 is that the calcination temperature during the preparation of the support SiO2 is lower, which is 400 °C, and the specific steps are as follows: The preparation steps of the lower-layer microporous catalyst are as follows: S1. Dissolve 10 mg of ethylene oxide in 90 mL of 1 mol / L nitric acid, then add 60 mg of tetraethyl orthosilicate. After sealing and stirring at room temperature for 30 min, dry at 40 °C for 2 days. Cut the obtained white gel into small pieces, wash them successively with water and ammonia water, and then wash with water again until neutral. After drying at 40 °C for 20 h, continue to dry at 110 °C for 8 h and calcine at 400 °C for 12 h to obtain the support SiO2; S2. Immerse 800 mg of the support SiO2 in 200 mL of 0.3 mg / mL Ni(NO3)2·6H2O solution, stir evenly, dry overnight to obtain a solid powder, and calcine at 550 °C for 4 h to obtain the lower-layer microporous catalyst Ni / SiO2. Comparative Example 4 The difference between this comparative example and Example 2 is that the calcination temperature during the preparation of the support SiO2 is higher, which is 700 °C, and the specific steps are as follows: The preparation steps of the lower-layer microporous catalyst are as follows: S1. Dissolve 10 mg of ethylene oxide in 90 mL of 1 mol / L nitric acid, then add 60 mg of tetraethyl orthosilicate. After sealing and stirring at room temperature for 30 min, dry at 40 °C for 2 days. Cut the obtained white gel into small pieces, wash them successively with water and ammonia water, and then wash with water again until neutral. After drying at 40 °C for 20 h, continue to dry at 110 °C for 8 h and calcine at 700 °C for 12 h to obtain the support SiO2; S2. Immerse 800 mg of the support SiO2 in 200 mL of 0.3 mg / mL Ni(NO3)2·6H2O solution, stir evenly, dry overnight to obtain a solid powder, and calcine at 550 °C for 4 h to obtain the lower-layer microporous catalyst Ni / SiO2. Table 1 Pore size and loading rate of the lower-layer microporous catalyst Ni / SiO2 prepared in Examples 1-5 and Comparative Examples 1-4 As can be seen from Table 1, the calcination temperature during the preparation of the support is related to the pore size, and the feed ratio of the support to the metal solution also determines the loading rate of metal ions. When the calcination temperature is too high, the pore size of the support prepared in Comparative Example 4 is relatively increased compared with that in the examples, the residence time of the intermediate in the lower-layer microporous catalyst will be shortened, the residue of the intermediate will increase, and thus the purity of the final product will be affected. The pore size of the lower-layer microporous catalyst Ni / SiO2 prepared in Example 2 of the present invention is 4 nm, and the loading rate is 13.7%. Therefore, the catalyst prepared in Example 2 is selected for the subsequent hydrogenation reaction of soybean phospholipid. Example 6 The preparation steps of the upper-layer macroporous catalyst are as follows: S1. Prepare a palladium chloride solution with a concentration of 1 mol / L; S2. Thoroughly rinse alumina with deionized water, dry it, calcine it at 600 °C for 3 h, cool it to room temperature, and activate it in a constant-temperature drying oven to obtain activated alumina; S3. Immerse the activated alumina into the active metal salt solution by the equal-volume impregnation method, assist with ultrasonic for 30 min, let it stand for 12 h, then dry it at 110 °C for 6 h and calcine it at 350 °C for 2 h to obtain the upper-layer macroporous catalyst with active metal supported on alumina. Example 7 The preparation steps of the upper-layer macroporous catalyst are as follows: S1. Prepare a palladium chloride solution with a concentration of 2 mol / L; S2. Thoroughly rinse alumina with deionized water, dry it, calcine it at 600 °C for 3 h, cool it to room temperature, and activate it in a constant-temperature drying oven to obtain activated alumina; S3. Immerse the activated alumina into the active metal salt solution by the equal-volume impregnation method, assist with ultrasonic for 30 min, let it stand for 12 h, then dry it at 110 °C for 6 h and calcine it at 350 °C for 2 h to obtain the upper-layer macroporous catalyst with active metal supported on alumina. Example 8 The preparation steps of the upper-layer macroporous catalyst are as follows: S1. Prepare a ruthenium chloride solution with a concentration of 2 mol / L; S2. Thoroughly rinse alumina with deionized water, dry it, calcine it at 600 °C for 3 h, cool it to room temperature, and activate it in a constant-temperature drying oven to obtain activated alumina; S3. The activated alumina was immersed in the active metal salt solution by the equal-volume impregnation method, ultrasonic-assisted for 30 min, allowed to stand for 12 h, dried at 110 °C for 6 h, and calcined at 350 °C for 2 h to obtain the upper macroporous catalyst with active metal supported on alumina. Example 9 The preparation steps of the upper macroporous catalyst are as follows: S1. Prepare a palladium chloride solution with a concentration of 2 mol / L; S2. The alumina was thoroughly rinsed with deionized water, dried, calcined at 400 °C for 3 h, cooled to room temperature, and activated in a constant-temperature drying oven to obtain activated alumina; S3. The activated alumina was immersed in the active metal salt solution by the equal-volume impregnation method, ultrasonic-assisted for 30 min, allowed to stand for 12 h, dried at 110 °C for 6 h, and calcined at 350 °C for 2 h to obtain the upper macroporous catalyst with active metal supported on alumina. Example 10 The preparation steps of the upper macroporous catalyst are as follows: S1. Prepare a palladium chloride solution with a concentration of 2 mol / L; S2. The alumina was thoroughly rinsed with deionized water, dried, calcined at 500 °C for 3 h, cooled to room temperature, and activated in a constant-temperature drying oven to obtain activated alumina; S3. The activated alumina was immersed in the active metal salt solution by the equal-volume impregnation method, ultrasonic-assisted for 30 min, allowed to stand for 12 h, dried at 110 °C for 6 h, and calcined at 350 °C for 2 h to obtain the upper macroporous catalyst with active metal supported on alumina. Comparative Example 5 The difference between this comparative example and Example 7 is that the concentration of the palladium chloride solution is lower, which is 0.5 mol / L, and the details are as follows: The preparation steps of the upper macroporous catalyst are as follows: S1. Prepare a palladium chloride solution with a concentration of 0.5 mol / L; S2. The alumina was thoroughly rinsed with deionized water, dried, calcined at 600 °C for 3 h, cooled to room temperature, and activated in a constant-temperature drying oven to obtain activated alumina; S3. The activated alumina was immersed in the active metal salt solution by the equal-volume impregnation method, ultrasonic-assisted for 30 min, allowed to stand for 12 h, dried at 110 °C for 6 h, and calcined at 350 °C for 2 h to obtain the upper macroporous catalyst with active metal supported on alumina. Comparative Example 6 The difference between this comparative example and Example 7 is that the concentration of the palladium chloride solution is higher, which is 3 mol / L, and the details are as follows: The preparation steps of the upper macroporous catalyst are as follows: S1. Prepare a palladium chloride solution with a concentration of 3 mol / L; S2. Thoroughly rinse the alumina with deionized water, dry it, calcine it at 600 °C for 3 h, cool it to room temperature, and activate it in a constant-temperature drying oven to obtain activated alumina; S3. Immerse the activated alumina in the active metal salt solution by the equal-volume impregnation method, assist with ultrasonic waves for 30 min, let it stand for 12 h, dry it at 110 °C for 6 h, and calcine it at 350 °C for 2 h to obtain the upper-layer macroporous catalyst with active metal supported on alumina. Comparative Example 7 The difference between this comparative example and Example 7 lies in that when preparing the activated alumina support, the calcination temperature is lower, at 300 °C, specifically as follows: The preparation steps of the upper-layer macroporous catalyst are as follows: S1. Prepare a palladium chloride solution with a concentration of 2 mol / L; S2. Thoroughly rinse the alumina with deionized water, dry it, calcine it at 300 °C for 3 h, cool it to room temperature, and activate it in a constant-temperature drying oven to obtain activated alumina; S3. Immerse the activated alumina in the active metal salt solution by the equal-volume impregnation method, assist with ultrasonic waves for 30 min, let it stand for 12 h, dry it at 110 °C for 6 h, and calcine it at 350 °C for 2 h to obtain the upper-layer macroporous catalyst with active metal supported on alumina. Comparative Example 8 The difference between this comparative example and Example 7 lies in that when preparing the activated alumina support, the calcination temperature is higher, at 700 °C, specifically as follows: The preparation steps of the upper-layer macroporous catalyst are as follows: S1. Prepare a palladium chloride solution with a concentration of 2 mol / L; S2. Thoroughly rinse the alumina with deionized water, dry it, calcine it at 700 °C for 3 h, cool it to room temperature, and activate it in a constant-temperature drying oven to obtain activated alumina; S3. Immerse the activated alumina in the active metal salt solution by the equal-volume impregnation method, assist with ultrasonic waves for 30 min, let it stand for 12 h, dry it at 110 °C for 6 h, and calcine it at 350 °C for 2 h to obtain the upper-layer macroporous catalyst with active metal supported on alumina. Table 2 Pore sizes and loadings of the upper-layer macroporous catalysts prepared in Examples 6 - 10 and Comparative Examples 5 - 8 As can be seen from Table 2, the calcination temperature during the preparation of the support is related to the pore size, and the concentration of the metal solution also determines the metal ion loading rate. When the calcination temperature is too high, the pore size of the support is relatively smaller than that of the examples, and the speed of soybean phospholipid passing through the upper macroporous catalyst is too fast, which will also make the hydrogenation reaction insufficient, affecting the yield and purity of the final product. The pore size of the upper macroporous catalyst prepared in Example 7 is 38 nm, and the loading rate is 8.7%. Therefore, the catalyst prepared in Example 7 is selected for the subsequent hydrogenation reaction of soybean phospholipid. Example 11 A method for continuously synthesizing hydrogenated lecithin by micro-fixed bed liquid-phase hydrogenation, comprising the following steps: 1) The lower microporous catalyst Ni / SiO2 prepared in Example 2 and the upper macroporous catalyst prepared in Example 7 are loaded into the hydrogenation reaction column in a volume ratio of 1:2 in sequence, with an inert ceramic fiber separation layer in the middle. During the loading process, gently tap to improve the packing density of the catalyst, prevent the catalyst from bridging, and purge with nitrogen during the loading process; 2) Dissolve 10 g of soybean phospholipid in 200 mL of tetrahydrofuran, stir and dissolve until clear to prepare a tetrahydrofuran solution of soybean phospholipid; 3) Control the reaction temperature at 40 °C, the reaction pressure at 2.5 Mpa, the flow rate of the tetrahydrofuran solution of soybean phospholipid at 0.2 mL / min, and the hydrogen flow rate at 30 mL / min; 4) First, pass the tetrahydrofuran solution of soybean phospholipid and hydrogen together through the gas-liquid distributor at the inlet of the hydrogenation reaction column to be evenly dispersed, and then enter the hydrogenation reaction column to uniformly contact the catalyst bed cross-section for hydrogenation reaction. During this process, keep continuous feeding. After flowing for 1 h, the reaction reaches a stable state; 5) After the hydrogenation reaction is completed, collect the outflowing reaction solution, namely the crude hydrogenated lecithin solution; 6) Concentrate the crude hydrogenated lecithin solution to remove the solvent to obtain hydrogenated lecithin; 7) After the reaction is completed, stop feeding, wash the catalyst bed with the same solvent as in step 2), then blow dry the washed catalyst bed with nitrogen, and under the nitrogen purge state, lead out the reacted catalyst from the hydrogenation reaction column and collect it in water. Example 12 A method for continuously synthesizing hydrogenated lecithin by micro-fixed bed liquid-phase hydrogenation, comprising the following steps: 1) The lower microporous catalyst Ni / SiO2 prepared in Example 2 and the upper macroporous catalyst prepared in Example 7 are loaded into the hydrogenation reaction column in a volume ratio of 1:2.5 in sequence, with an inert ceramic fiber separation layer in the middle. During the loading process, gently tap to improve the packing density of the catalyst, prevent the catalyst from bridging, and purge with nitrogen during the loading process; 2) Dissolve 10 g of soy lecithin in 200 mL of tetrahydrofuran, stir until dissolved and clarified to prepare a tetrahydrofuran solution of soy lecithin; 3) Control the reaction temperature at 40 °C, the reaction pressure at 2.5 Mpa, the flow rate of the tetrahydrofuran solution of soy lecithin at 0.2 mL / min, and the hydrogen flow rate at 30 mL / min; 4) First, pass the tetrahydrofuran solution of soy lecithin and hydrogen together through the gas-liquid distributor at the inlet of the hydrogenation reaction column to be evenly dispersed, and then enter the hydrogenation reaction column to uniformly contact the cross-section of the catalyst bed to occur hydrogenation reaction. During this process, continuous feeding is maintained. After flowing for 1 h, the reaction reaches a stable state; 5) After the hydrogenation reaction is completed, collect the outflowing reaction solution, that is, the crude hydrogenated lecithin solution; 6) Concentrate the crude hydrogenated lecithin solution to remove the solvent to obtain hydrogenated lecithin; 7) After the reaction is completed, stop feeding, wash the catalyst bed with the same solvent as in step 2), then blow dry the washed catalyst bed with nitrogen, and under the nitrogen purging state, lead out the reacted catalyst from the hydrogenation reaction column and collect it in water. Example 13 A method for synthesizing hydrogenated lecithin by micro-fixed bed liquid-phase continuous hydrogenation, comprising the following steps: 1) Load the lower-layer microporous catalyst Ni / SiO2 prepared in Example 2 and the upper-layer macroporous catalyst prepared in Example 7 into the hydrogenation reaction column in a volume ratio of 1:3 in sequence, with an inert ceramic fiber separation layer in the middle. During the loading process, gently tap to improve the packing density of the catalyst, prevent the catalyst from bridging, and purge with nitrogen during the loading process; 2) Dissolve 10 g of soy lecithin in 200 mL of tetrahydrofuran, stir until dissolved and clarified to prepare a tetrahydrofuran solution of soy lecithin; 3) Control the reaction temperature at 40 °C, the reaction pressure at 2.5 Mpa, the flow rate of the tetrahydrofuran solution of soy lecithin at 0.2 mL / min, and the hydrogen flow rate at 30 mL / min; 4) First, pass the tetrahydrofuran solution of soy lecithin and hydrogen together through the gas-liquid distributor at the inlet of the hydrogenation reaction column to be evenly dispersed, and then enter the hydrogenation reaction column to uniformly contact the cross-section of the catalyst bed to occur hydrogenation reaction. During this process, continuous feeding is maintained. After flowing for 1 h, the reaction reaches a stable state; 5) After the hydrogenation reaction is completed, collect the outflowing reaction solution, that is, the crude hydrogenated lecithin solution; 6) Concentrate the crude hydrogenated lecithin solution to remove the solvent to obtain hydrogenated lecithin; 7) After the reaction is completed, stop feeding, wash the catalyst bed with the same solvent as in step 2), then dry the washed catalyst bed with nitrogen, and under the nitrogen purging state, remove the reacted catalyst from the hydrogenation reaction column and collect it in water. Comparative Example 9 The difference between this comparative example and Example 11 is that the catalyst only contains the upper macroporous catalyst prepared in Example 7. Specifically, a method for continuously synthesizing hydrogenated lecithin by micro-fixed bed liquid-phase hydrogenation includes the following steps: 1) Load the upper macroporous catalyst prepared in Example 7 into the hydrogenation reaction column. During the loading process, gently tap to improve the packing density of the catalyst, prevent the catalyst from bridging, and purge with nitrogen during the loading process; 2) Dissolve 10 g of soybean phospholipid in 200 mL of tetrahydrofuran, stir and dissolve until clear to prepare a tetrahydrofuran solution of soybean phospholipid; 3) Control the reaction temperature at 40 °C, the reaction pressure at 2.5 Mpa, the flow rate of the tetrahydrofuran solution of soybean phospholipid at 0.2 mL / min, and the hydrogen flow rate at 30 mL / min; 4) First, pass the tetrahydrofuran solution of soybean phospholipid and hydrogen together through the gas-liquid distributor at the inlet of the hydrogenation reaction column to be evenly dispersed, and then enter the hydrogenation reaction column to uniformly contact the cross-section of the catalyst bed for hydrogenation reaction. During this process, keep continuous feeding. After flowing for 1 h, the reaction reaches a stable state; 5) After the hydrogenation reaction is completed, collect the outflowing reaction solution, namely the crude hydrogenated lecithin solution; 6) Concentrate the crude hydrogenated lecithin solution to remove the solvent to obtain hydrogenated lecithin; 7) After the reaction is completed, stop feeding, wash the catalyst bed with the same solvent as in step 2), then dry the washed catalyst bed with nitrogen, and under the nitrogen purging state, remove the reacted catalyst from the hydrogenation reaction column and collect it in water. Comparative Example 10 The difference between this comparative example and Example 11 is that the catalyst only contains the lower microporous catalyst prepared in Example 2. Specifically, a method for continuously synthesizing hydrogenated lecithin by micro-fixed bed liquid-phase hydrogenation includes the following steps: 1) Load the lower microporous catalyst Ni / SiO2 prepared in Example 2 into the hydrogenation reaction column. During the loading process, gently tap to improve the packing density of the catalyst, prevent the catalyst from bridging, and purge with nitrogen during the loading process; 2) Dissolve 10 g of soybean phospholipid in 200 mL of tetrahydrofuran, stir and dissolve until clear to prepare a tetrahydrofuran solution of soybean phospholipid; 3) Control the reaction temperature at 40 °C, the reaction pressure at 2.5 Mpa, the flow rate of the tetrahydrofuran solution of soybean phospholipid at 0.2 mL / min, and the hydrogen flow rate at 30 mL / min; 4) First, pass the tetrahydrofuran solution of soybean phospholipid and hydrogen together through the gas-liquid distributor at the inlet of the hydrogenation reaction column to be evenly dispersed, and then enter the hydrogenation reaction column to uniformly contact the cross-section of the catalyst bed and undergo a hydrogenation reaction. During this process, continuous feeding is maintained. After flowing for 1 h, the reaction reaches a stable state; 5) After the hydrogenation reaction is completed, collect the outflowing reaction solution, i.e., the crude hydrogenated lecithin solution; 6) Concentrate the crude hydrogenated lecithin solution to remove the solvent and obtain hydrogenated lecithin; 7) After the reaction ends, stop feeding, wash the catalyst bed with the same solvent as in step 2), then blow dry the washed catalyst bed with nitrogen, and under the nitrogen purging state, lead out the reacted catalyst from the hydrogenation reaction column and collect it in water. Comparative Example 11 The difference between this comparative example and Example 11 is that the volume ratio of the lower-layer microporous catalyst to the upper-layer macroporous catalyst is 1:1, specifically as follows: A method for continuously synthesizing hydrogenated lecithin by micro-fixed bed liquid-phase hydrogenation includes the following steps: 1) Load the lower-layer microporous catalyst Ni / SiO2 prepared in Example 2 and the upper-layer macroporous catalyst prepared in Example 7 into the hydrogenation reaction column in sequence according to a volume ratio of 1:1, with an inert ceramic fiber separator layer in the middle. During the loading process, gently tap to improve the packing density of the catalyst, prevent catalyst bridging, and purge with nitrogen during the loading process; 2) Dissolve 10 g of soybean phospholipid in 200 mL of tetrahydrofuran, stir and dissolve until clear to prepare a tetrahydrofuran solution of soybean phospholipid; 3) Control the reaction temperature at 40 °C, the reaction pressure at 2.5 Mpa, the flow rate of the tetrahydrofuran solution of soybean phospholipid at 0.2 mL / min, and the hydrogen flow rate at 30 mL / min; 4) First, pass the tetrahydrofuran solution of soybean phospholipid and hydrogen together through the gas-liquid distributor at the inlet of the hydrogenation reaction column to be evenly dispersed, and then enter the hydrogenation reaction column to uniformly contact the cross-section of the catalyst bed and undergo a hydrogenation reaction. During this process, continuous feeding is maintained. After flowing for 1 h, the reaction reaches a stable state; 5) After the hydrogenation reaction is completed, collect the outflowing reaction solution, i.e., the crude hydrogenated lecithin solution; 6) Concentrate the crude hydrogenated lecithin solution to remove the solvent and obtain hydrogenated lecithin; 7) After the reaction is completed, stop feeding, wash the catalyst bed with the same solvent as in step 2), then dry the washed catalyst bed with nitrogen, and under the nitrogen purging state, lead out the reacted catalyst from the hydrogenation reaction column and collect it in water. Comparative Example 12 The difference between this comparative example and Example 11 is that the hydrogen flow rate is too fast, specifically as follows: A method for continuously synthesizing hydrogenated lecithin by micro fixed-bed liquid-phase hydrogenation, comprising the following steps: 1) Load the lower-layer microporous catalyst Ni / SiO2 prepared in Example 2 and the upper-layer macroporous catalyst prepared in Example 7 into the hydrogenation reaction column in a volume ratio of 1:2 in sequence, with an inert ceramic fiber separation layer in the middle. During the loading process, gently tap to improve the packing density of the catalyst, prevent catalyst bridging, and purge with nitrogen during the loading process; 2) Dissolve 10 g of soybean phospholipid in 200 mL of tetrahydrofuran, stir and dissolve until clear to prepare a tetrahydrofuran solution of soybean phospholipid; 3) Control the reaction temperature at 40 °C, the reaction pressure at 2.5 Mpa, the flow rate of the tetrahydrofuran solution of soybean phospholipid at 0.2 mL / min, and the hydrogen flow rate at 50 mL / min; 4) First, pass the tetrahydrofuran solution of soybean phospholipid and hydrogen together through the gas-liquid distributor at the inlet of the hydrogenation reaction column, disperse them evenly, and then enter the hydrogenation reaction column, and contact the catalyst bed cross-section evenly to carry out the hydrogenation reaction. During this process, keep continuous feeding. After flowing for 1 h, the reaction reaches a stable state; 5) After the hydrogenation reaction is completed, collect the outflowing reaction solution, namely the crude hydrogenated lecithin solution; 6) Concentrate the crude hydrogenated lecithin solution to remove the solvent to obtain hydrogenated lecithin; 7) After the reaction is completed, stop feeding, wash the catalyst bed with the same solvent as in step 2), then dry the washed catalyst bed with nitrogen, and under the nitrogen purging state, lead out the reacted catalyst from the hydrogenation reaction column and collect it in water. Comparative Example 13 The difference between this comparative example and Example 11 is that the hydrogenated lecithin is prepared by a kettle hydrogenation process, specifically as follows: 1) Charge 16 kg of soybean phospholipid and 160 L of methanol (10 times the volume) into a 200 L high-pressure hydrogenation kettle in sequence; 2) After stirring and dissolving, add 0.8 kg of 5% ruthenium / carbon catalyst (water content 50%). After purging with nitrogen three times, control the reaction temperature at 55 °C, slowly introduce hydrogen. After the temperature stabilizes, raise the hydrogen pressure to 2 Mpa and continue the reaction for 20 h; 3) After the reaction is completed, filter, return the filtered catalyst to the reactor for reuse, and perform the feeding operation and hydrogenation reaction again. Each batch of catalyst can be reused 3 times; 4) Combine the filtrates of 3 batches and concentrate them, then recrystallize with a toluene-ethanol mixed solvent with a volume ratio of 2:1 to obtain hydrogenated lecithin. Yield and purity evaluation tests: Yield (%) = (W1 / W2) × 100%, where W1 is the mass of the actually obtained hydrogenated lecithin; W2 is the mass of the theoretically obtained hydrogenated lecithin; Purity: Using high performance liquid chromatography; the detector is an evaporative light scattering detector; the chromatographic column is Alltima Silica, 250mm × 4.6mm, 5μm; the column temperature is 40°C; Iodine value: GB / T 5532-2022 "Determination of iodine value of animal and vegetable fats and oils". Table 3 Yield, purity and iodine value of hydrogenated lecithin prepared in Examples 11-13 and Comparative Examples 9-13 As can be seen from Table 3, the yields of hydrogenated lecithin in Examples 11-13 are 92.1-95.8%, the purities are 96.4-99.2%, and the iodine values are 4.2-5.8 gI2 / 100g. However, for Comparative Example 9 with only the upper macroporous catalyst, Comparative Example 10 with only the lower microporous catalyst, and Comparative Example 11 with a volume ratio of 1:1 of the lower microporous catalyst to the upper macroporous catalyst, the yields and purities of the generated hydrogenated lecithin both decrease; in Comparative Example 12, when the hydrogenation flow rate is too fast, soybean phospholipid cannot react fully with hydrogen, resulting in a decrease in both yield and purity; in Comparative Example 13, the hydrogenated lecithin is prepared by a kettle hydrogenation process, and the catalyst is coated on the reactor wall, and the mass transfer effect is not essentially improved, so the yield and purity also decrease accordingly. For the iodine value, the more complete the hydrogenation, the lower the iodine value. The iodine values of the hydrogenated lecithin prepared in the examples of the present invention are all lower than those of the comparative examples. It can be seen that the lower microporous catalyst and the upper macroporous catalyst used in the examples can generate hydrogenated lecithin more completely and efficiently. The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for continuously synthesizing hydrogenated lecithin by micro-fixed bed liquid-phase hydrogenation, characterized in that: Introduce the soybean phospholipid solution and hydrogen into the hydrogenation reaction column for reaction to obtain a crude hydrogenated lecithin solution, and then concentrate the crude hydrogenated lecithin solution to remove the solvent to obtain hydrogenated lecithin; Among them, a catalyst bed layer is provided in the hydrogenation reaction column. The catalyst bed layer is filled with a lower-layer microporous catalyst and an upper-layer macroporous catalyst in sequence from bottom to top, with a volume ratio of 1:(2 - 3), and an inert ceramic fiber separation layer is contained in the middle.

2. The method for synthesizing hydrogenated lecithin by continuous hydrogenation in a micro-fixed bed in liquid phase according to claim 1, wherein: The carrier of the lower-layer microporous catalyst is SiO2, and transition metal Ni is loaded on the carrier, with a pore size of 4 - 7nm; the carrier of the upper-layer macroporous catalyst is alumina, and an active metal is loaded on the carrier, with a pore size of 32 - 38nm.

3. A method for synthesizing hydrogenated lecithin by continuous hydrogenation in a micro-fixed bed in liquid phase according to claim 2, characterized in that, The preparation steps of the lower-layer microporous catalyst are as follows: S1. Dissolve ethylene oxide in 1mol / L nitric acid, then add tetraethyl orthosilicate, seal and stir at room temperature for 30 - 40min, dry at 40℃ for 2 - 3 days, cut the obtained white gel into small pieces, wash successively with water and ammonia water, and then wash with water again until neutral, dry at 40℃ for 20 - 24h, continue to dry at 100 - 110℃ for 6 - 12h, and calcine at 500 - 600℃ for 10 - 12h to obtain the carrier SiO2; S2. Immerse the carrier SiO2 in a 0.3 - 0.4mg / mL Ni(NO3)2·6H2O solution with a mass-to-volume ratio of 8mg:(1 - 3)mL, stir evenly, dry overnight to obtain a solid powder, and calcine at 500 - 550℃ for 3 - 4h to obtain the lower-layer microporous catalyst Ni / SiO2.

4. A method for synthesizing hydrogenated lecithin by continuous hydrogenation in a micro fixed bed in liquid phase according to claim 3, characterized in that, In the step S1, the mass-to-volume ratio of ethylene oxide, tetraethyl orthosilicate and nitric acid is 1g:(6 - 7)g:(8 - 9)mL.

5. A method for synthesizing hydrogenated lecithin by continuous hydrogenation in a micro-fixed bed in liquid phase according to claim 2, wherein, The preparation steps of the upper-layer macroporous catalyst are as follows: S1. Prepare an active metal salt solution with a concentration of 1 - 2mol / L; S2. Thoroughly rinse alumina with deionized water, dry it, calcine it at 400 - 600℃ for 2 - 4h, cool it to room temperature, and place it in a constant-temperature drying oven for activation to obtain activated alumina; S3. Immerse the activated alumina in the active metal salt solution by the equal-volume impregnation method, assist with ultrasonic waves for 30 - 60min, let it stand for 12h, then dry at 100 - 110℃ for 5 - 6h, and calcine at 300 - 350℃ for 2 - 3h to obtain the upper-layer macroporous catalyst with an active metal loaded on alumina.

6. A method for synthesizing hydrogenated lecithin by continuous hydrogenation in a micro-fixed bed in liquid phase according to claim 5, characterized in that: The active metal is one or more of palladium, platinum, and ruthenium; the loading amount of the active metal is 0.5 - 10%.

7. A method for synthesizing hydrogenated lecithin by continuous hydrogenation in a micro-fixed bed in liquid phase according to claim 1, characterized in that, Specifically, it includes the following steps: 1) Load the catalyst into the hydrogenation reaction column and purge it with nitrogen during the loading process; 2) Dissolve soybean phospholipid in a solvent to obtain a soybean phospholipid solution; 3) Regulate the reaction temperature in the hydrogenation reaction column through a temperature control device, and regulate the reaction pressure in the hydrogenation reaction column through a pressure regulating device; 4) Pass the soybean phospholipid solution and hydrogen together through the gas-liquid distributor at the inlet of the hydrogenation reaction column to be evenly dispersed, and then enter the hydrogenation reaction column to uniformly contact the cross-section of the catalyst bed layer to carry out the hydrogenation reaction. During this process, continuous feeding is maintained; 5) After the hydrogenation reaction is completed, collect the outflowing reaction solution, which is the crude hydrogenated lecithin solution; 6) Concentrate the crude hydrogenated lecithin solution to remove the solvent and obtain hydrogenated lecithin. 7) After the reaction is completed, stop feeding, wash the catalyst bed with the same solvent as in step 2), then dry the washed catalyst bed with nitrogen, and under the nitrogen purge state, lead out the reacted catalyst from the hydrogenation reaction column and collect it in water.

8. A method for continuously synthesizing hydrogenated lecithin by micro-fixed bed liquid-phase hydrogenation according to claim 7, characterized in that: In the said step 2), the mass-volume ratio of soybean phospholipid to the solvent is 1 g : (10 - 30) mL; the solvent is any one of tetrahydrofuran, dichloromethane, ethanol, and n-hexane.

9. A method for synthesizing hydrogenated lecithin by continuous hydrogenation in a micro-fixed bed in liquid phase according to claim 7, characterized in that: In the said step 3), the reaction temperature is 30 - 80 °C and the reaction pressure is 1 - 5 Mpa.

10. A method for continuously synthesizing hydrogenated lecithin by micro-fixed bed liquid-phase continuous hydrogenation according to claim 7, characterized in that: In the said step 4), the flow rate of the soybean phospholipid solution is 0.02 - 0.2 mL / min; the flow rate of the hydrogen is 20 - 40 mL / min.

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