Continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents

Abstract

The invention discloses a continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents, and belongs to the technical field of organic synthesis. According to the method, methanol is used as a green hydrogen source and a methyl source, and the reaction conditions and the catalyst are modulated, so that hydrogenated lecithin products with phosphatidylcholine PC contents of more than or equal to 20%, more than or equal to 80% and more than or equal to 98% can be prepared by taking lecithin as a raw material, the liquid holdup of a reaction system is reduced while the reaction efficiency is improved, the process risk is fundamentally reduced, and the production cost is reduced. And different market requirements are met.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents. Background Art

[0002] Hydrogenated lecithin is usually synthesized from soybean lecithin through a catalytic hydrogenation process. After lecithin is hydrogenated to hydrogenated lecithin, the unsaturated bonds of unsaturated fatty acids in the molecular structure of soybean lecithin are reduced, which can greatly improve the chemical stability, dispersibility, and emulsification of lecithin. The hydrogenation process also has the effect of decolorization and deodorization, which is more conducive to the storage and preservation of (hydrogenated) lecithin products, and improves its role in medicine, high-end cosmetics, and light industry.

[0003] In 1933, Shinozaki et al. (Shinozaki, S., Sato, M., Hydrogenation of lecithin isolated from the soybean. Nippon Nogei Kagaku Kaishi, 1933, 9, 728.) used colloidal palladium to catalyze the hydrogenation of lecithin isolated from soybean lecithin to obtain a product with a melting point of 85°C and insoluble in MeOAc. In 1934, Shinozald et al. (Shinozaki, Y., Sato, M., The hydrogenation under high pressure. Kogyo Kagaku Zasshi, 1934, 37, 432.) used Ni catalyst and reaction pressure above 80 atm to obtain hydrogenated lecithin with an iodine value of 0.38 and a melting point of 84°C. Jin Xijiang et al. (Development of Hydrogenated Soybean Lecithin, Fine Chemicals, 1999, 16, 5.) used Pd / C as a catalyst and dichloromethane as a solvent for catalytic hydrogenation, and obtained light yellow hydrogenated soybean lecithin with an iodine value of less than 30. He Fengying et al. (Preparation of Hydrogenated Soybean Lecithin, Hunan Chemical Industry, 1999, 29, 18.) selected palladium catalyst and dichloromethane or dichloromethane-ethanol mixture as solvent, separated the reaction product, and obtained hydrogenated soybean lecithin with an iodine value of 20-30, light yellow color, no unpleasant odor, and a yield of 80%. Japanese patent JP0403629 reported the use of a mixed solvent of n-heptane and C1-4 lower alcohol as solvent, and Pt as a catalyst for catalytic hydrogenation of lecithin, and 90% hydrogenated lecithin can be obtained at a temperature of 80°C. The hydrogenation reaction can be qualitatively characterized by the iodine value. The lower the iodine value, the more complete the hydrogenation. Although there are many patent documents that study the catalytic processes of palladium, platinum, nickel and other catalysts under different reaction conditions, all current lecithin hydrogenation technologies use kettle hydrogenation methods. As one of the 18 types of hazardous chemical processes that are subject to national key supervision, the hydrogenation reaction has high explosion hazards in its reaction materials, hydrogenation catalysts and reaction tail gas. In addition, hydrogenation is a strong exothermic reaction. When hydrogen comes into contact with steel under high temperature and pressure, the carbon molecules in the steel easily react with hydrogen to form hydrocarbons, which reduces the strength of steel equipment and causes hydrogen embrittlement.

[0004] The hydrogen transfer reaction is considered to be a safer and greener ideal route for the reduction of unsaturated compounds. Methanol is an ideal hydrogen source that has attracted much attention in recent years. Its hydrogen mass density is 12.5wt%, and it has significant advantages such as low toxicity, wide sources, biodegradability, and safe and convenient storage and transportation. If a suitable hydrogen transfer hydrogenation catalyst can be developed, a green synthesis route for hydrogenated lecithin using green methanol as the hydrogen source can be realized.

[0005] Crude soybean lecithin is a mixture of phospholipids, including phosphatidylcholine PC (lecithin, content of about 25% to 32%), phosphatidylethanolamine PE (cephalin, 18% to 21%), phosphatidylinositol PI (inositol phospholipids), phosphatidylglycerol PG (sphingomyelin), phosphatidic acid PA, other phospholipids, etc. Among them, phosphatidylethanolamine PE can be converted into phosphatidylcholine PC through methylation reaction, thereby increasing the phosphatidylcholine PC content of the product. In addition to being an ideal hydrogen source, methanol is also an ideal methylation agent. For the reaction process of preparing hydrogenated lecithin from soybean lecithin, if the reaction conditions can be adjusted based on the methanol-activated hydrogen transfer catalytic reaction, and the multifunctional tandem reaction of methanol dehydrogenation, phosphatidylethanolamine PE methylation, and double bond hydrogen transfer hydrogenation can be achieved at the same time, then lecithin products with higher PC content can be further prepared to meet different market demands.

[0006] In addition, the traditional intermittent hydrogenation process is limited by conditions such as reaction temperature and pressure, and has problems such as high safety requirements for hydrogen and reaction equipment, long reaction time, low conversion rate, and difficulty in controlling over-reduction. Continuous flow microchannel reaction can not only strengthen the reaction process, but also can be used as a safer, faster and more efficient reaction process in drug synthesis and fine chemicals. In the continuous flow microchannel reaction process, the gas-liquid-solid contact is strengthened, which enhances the mass transfer effect between the phases of the gas-liquid-solid (catalyst) multiphase catalytic system, thereby increasing the reaction rate. The precise controllability of reaction temperature, pressure and catalyst contact time in the flow system also makes rapid optimization and reproduction of reaction conditions possible. More importantly, the low liquid holdup characteristic of continuous flow hydrogenation technology can greatly reduce the danger of intermittent hydrogenation process. Summary of the invention

[0007] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0008] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0009] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a continuous flow preparation process for hydrogenated lecithin with different phosphatidylcholine contents.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions, including:

[0011] Lecithin is dissolved in a solvent, and the resulting reaction solution is continuously pumped into a micro-packed bed reaction module filled with a hydrogen transfer reduction catalyst, where methylation and catalytic hydrogen transfer reduction reactions are performed under the action of the catalyst;

[0012] The reacted material is cooled in a cooler and then concentrated to obtain a crude hydrogenated lecithin, which is then pulped and purified to obtain hydrogenated lecithin.

[0013] As a preferred embodiment of the continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents of the present invention, the lecithin comprises one or more of soybean lecithin, rapeseed lecithin or egg yolk lecithin;

[0014] The lecithin is selected according to the PC content of the target product;

[0015] When the PC content of the target product is less than 80% by 20%, the PC content of the lecithin is 20% to 35%;

[0016] When the PC content of the target product is ≥80%, the PC content of the lecithin is 70% to 75%.

[0017] As a preferred embodiment of the continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents described in the present invention, the solvent includes one or more of methanol, ethanol, isopropanol, dichloromethane, n-hexane, n-heptane, toluene and chlorobenzene.

[0018] As a preferred solution of the continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents of the present invention, the mass fraction of lecithin in the reaction solution is 10% to 50%.

[0019] As a preferred solution of the continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents of the present invention, the pumping speed of the reaction solution is 0.3-2.0 mL / min.

[0020] As a preferred scheme of the continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents described in the present invention, the loading amount of the hydrogen transfer reduction catalyst is 15 to 20 g; the hydrogen transfer reduction catalyst is a supported nano metal catalyst with a metal loading amount of 0.1 to 5.0 wt%, and the carrier of the supported nano metal catalyst includes one of aluminum oxide, silicon oxide, zinc oxide, cerium oxide, titanium oxide, magnesium oxide, and zirconium oxide; the active metal supported by the supported nano metal catalyst includes one of Pt, Ir, Ru, and Pd; and the average particle size of the active metal is 1 to 20 nm.

[0021] As a preferred scheme for the continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents described in the present invention, the micro-packed bed reaction module is cylindrical, the hydrogen transfer reduction catalyst fills the internal space of the micro-packed bed reaction module, and the reaction liquid flows along the axial direction of the micro-packed bed reaction module; wherein the aspect ratio of the micro-packed bed reaction module is 10 to 60:1, and the ratio of the inner diameter of the micro-packed bed reaction module to the average particle size of the hydrogen transfer reduction catalyst is 15 to 30:1.

[0022] As a preferred solution of the continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents of the present invention, the temperature of the reaction module is selected according to the PC content of the target product;

[0023] When the PC content of the target product is less than 80% and the temperature of the reaction module is 80°C to 120°C;

[0024] When the PC content of the target product is ≥80%, the temperature of the reaction module is 120°C to 180°C;

[0025] The reaction time is 30 to 600 seconds.

[0026] As a preferred scheme of the continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents described in the present invention, the pulping solvent includes one or more of methanol, ethanol, isopropanol, dichloromethane, n-hexane, n-heptane, acetone, and toluene.

[0027] As a preferred embodiment of the continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents described in the present invention, the purification condition is recrystallization or column chromatography; the recrystallization solvent includes one or more of methanol, ethanol, isopropanol, dichloromethane, n-hexane, n-heptane, acetone, and toluene; the column chromatography solvent includes one or more of petroleum ether, dichloromethane, n-hexane, n-heptane, and toluene.

[0028] Beneficial effects of the present invention:

[0029] (1) Compared with the existing intermittent kettle hydrogenation process, the process of the present invention has a high degree of automation and safety factor, an economical and environmentally friendly production process, and is more suitable for industrial scale-up production.

[0030] (2) The present invention uses methanol as a green hydrogen source and a methyl source to develop a continuous preparation process for hydrogenated lecithin with different PC contents. By adjusting the reaction conditions and the catalyst, hydrogenated lecithin products with phosphatidylcholine PC contents of ≥20%, ≥80% and ≥98% can be prepared using lecithin as a raw material. While improving the reaction efficiency, the liquid holding capacity of the reaction system is reduced, thereby fundamentally reducing the process risk and meeting different market demands. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0032] Figure 1 Schematic diagram of a continuous reactor for lecithin hydrogenation; wherein 1 is the lecithin reaction liquid, 2 is the microreactor, 3 is the temperature control module, 4 is the cooler, and 5 is the product collection tank.

[0033] Figure 2 This is a graph showing the HPLC result of hydrogenated lecithin with a PC content ≥ 20% obtained in Example 1 of the present invention.

[0034] Figure 3 This is a graph showing the HPLC result of hydrogenated lecithin with a PC content ≥ 80% obtained in Example 8 of the present invention.

[0035] Figure 4 This is a graph showing the HPLC results of hydrogenated lecithin with a PC content ≥ 98% obtained in Example 11 of the present invention. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0039] The raw materials used in the present invention are all commercially available unless otherwise specified.

[0040] The yield is calculated as yield=(W1 / W2)×100%, wherein W1 is the mass of hydrogenated lecithin actually obtained, and W2 is the mass of hydrogenated lecithin theoretically obtained.

[0041] Iodine value: Determined by titration, the determination method refers to the national standard GBT5532-2022.

[0042] PC content: Detected by high performance liquid chromatography, the detection method refers to the national standard GBT35867-2018.

[0043] Example 1

[0044] This embodiment provides a method for preparing hydrogenated lecithin with 20%≤phosphatidylcholine (PC)<80%, referring to Figure 1 , specifically:

[0045] (1) dissolving soybean lecithin with a PC content of 20% and an iodine value of 79.0 in a mixed solution of toluene:methanol (v:v) = 1:1 to prepare a reaction solution with a mass fraction of 20%;

[0046] (2) The reaction solution was pumped into the reaction module of the continuous flow microreactor at a flow rate of 1 mL / min. The reaction module was cylindrical, with an inner diameter of 5 mm and a length of 50 mm. The interior was filled with 15 g of activated alumina-supported Pt catalyst (Pt content was 0.5%, and the average Pt particle size was 3.0 nm). The reaction module temperature was 110°C, the pressure was 3 MPa, and the residence time was 1 min.

[0047] (3) The reacted material enters a gas-liquid separator for cooling. The reaction liquid is concentrated and dried to obtain a crude hydrogenated lecithin product, which is then pulped with a methanol:acetone = 1:1 mixed solution to obtain a light yellow hydrogenated lecithin product.

[0048] The PC content of the above target product was determined by HPLC. Figure 2 As shown, the result is that the PC content is ≥30%; the iodine value is determined by titration, and the result is 5.

[0049] According to the above data, the obtained reaction product is hydrogenated lecithin.

[0050] Example 2

[0051] The difference between this embodiment and embodiment 1 is that the temperature of the reaction module is adjusted to 80° C., and the rest of the preparation process is the same as that of embodiment 1 to obtain a hydrogenated lecithin product.

[0052] Example 3

[0053] The difference between this embodiment and embodiment 1 is that the temperature of the reaction module is adjusted to 120° C., and the rest of the preparation process is the same as that of embodiment 1 to obtain a hydrogenated lecithin product.

[0054] The products obtained in the above examples were tested, and the comparison results with those in Example 1 are shown in Table 1.

[0055] Table 1

[0056] Example 1 Example 2 Example 3 Iodine value 5 23 6 PC content (%) 23.4 22.0 23.1

[0057] As can be seen from the table above, adjusting the temperature of the reaction module has a significant effect on the hydrogenation effect (i.e., the iodine value of the product). This is because the reaction temperature is too low, and methanol cannot be efficiently dehydrogenated, resulting in incomplete hydrogen transfer hydrogenation, which makes the iodine value of the product higher; when the hydrogenation reaches a certain level (iodine value <10), the temperature continues to rise, and the efficiency of hydrogen transfer hydrogenation cannot be further promoted, that is, the iodine value cannot be further reduced. According to the results in the table above, for the preparation of hydrogenated lecithin products with 30%≤phosphatidylcholine (PC)≤80%, the best technical effect can be obtained when the temperature of the reaction module is 110°C.

[0058] Example 4

[0059] The difference between this embodiment and embodiment 1 is that the reaction solution is adjusted to toluene:ethanol (v:v)=1:1, and the rest of the preparation process is the same as that of embodiment 1 to obtain a hydrogenated lecithin product.

[0060] Example 5

[0061] The difference between this embodiment and embodiment 1 is that the reaction solution is adjusted to n-heptane:methanol (v:v)=1:1, and the rest of the preparation process is the same as that of embodiment 1 to obtain a hydrogenated lecithin product.

[0062] The products obtained in the above examples were tested, and the comparison results with those in Example 1 are shown in Table 2.

[0063] Table 2

[0064] Example 1 Example 4 Example 5 Iodine value 5 65 42 PC content (%) 23.4 20.6 22.1

[0065] As can be seen from the above table, changing the reaction solvent has a significant effect on the iodine value of the product. This is because under the reaction conditions, when ethanol is used as the hydrogen source, the hydrogen transfer hydrogenation reaction of lecithin is not good; when n-heptane is used as the solvent, the methanol dehydrogenation effect becomes worse, resulting in a worse hydrogen transfer hydrogenation reaction effect, that is, a higher iodine value. According to the results in the above table, the best technical effect can be obtained when toluene: methanol (v:v) = 1:1 is used as the solvent in the present invention.

[0066] Example 6

[0067] The difference between this embodiment and embodiment 1 is that the length of the reaction module is adjusted to 300 mm, that is, the aspect ratio is 60:1, and the rest of the preparation process is the same as that of embodiment 1 to obtain a hydrogenated lecithin product.

[0068] Example 7

[0069] The difference between this embodiment and embodiment 1 is that the length of the reaction module is adjusted to 25 mm, that is, the aspect ratio is 5:1, and the rest of the preparation process is the same as that of embodiment 1 to obtain a hydrogenated lecithin product.

[0070] The products obtained in the above examples were tested, and the comparison results with those in Example 1 are shown in Table 3.

[0071] Table 3

[0072] Example 1 Example 6 Example 7 Iodine value 5 12 33 PC content (%) 23.4 21.4 22.3

[0073] As can be seen from the above table, changing the aspect ratio of the reaction module has a significant effect on the hydrogenation effect of the product. An aspect ratio that is too large will cause the reaction liquid to stay in the reaction module for too long, thereby causing an increase in side reactions or excessive hydrogenation of the product. An aspect ratio that is too small will result in insufficient residence time of the reaction liquid, the hydrogenation reaction may not reach the expected level, the reaction is incomplete, and the degree of hydrogenation of the product is insufficient, and the quality of the hydrogenated lecithin may not meet the requirements. In summary, the aspect ratio of the reaction module of the present invention is preferably 10:1.

[0074] Example 8

[0075] This embodiment provides a method for preparing hydrogenated lecithin with 80%≤phosphatidylcholine (PC)<98%, specifically:

[0076] (1) dissolving egg yolk lecithin with a PC content of 70% in a mixed solution of toluene:methanol (v:v) = 1:1 to prepare a reaction solution with a mass fraction of 20%;

[0077] (2) The reaction solution was pumped into the reaction module of the continuous flow microreactor at a flow rate of 1 mL / min. The reaction module was cylindrical, with an inner diameter of 5 mm and a length of 50 mm. The interior was filled with 15 g of activated alumina-supported Pt catalyst (Pt content was 0.5%, and the average Pt particle size was 3.0 nm). The reaction module temperature was 150°C, the pressure was 3 MPa, and the residence time was 1 min.

[0078] (3) The reacted material enters a gas-liquid separator for cooling. The reaction solution is concentrated and dried to obtain a crude hydrogenated lecithin product, which is recrystallized using a mixed solution of n-heptane:acetone = 1:1 to obtain a white hydrogenated lecithin product. The HPLC results are shown in Figure 3 .

[0079] Example 9

[0080] The difference between this embodiment and embodiment 6 is that the temperature of the reaction module is adjusted to 120° C., and the rest of the preparation process is the same as that of embodiment 1 to obtain a hydrogenated lecithin product.

[0081] Example 10

[0082] The difference between this embodiment and embodiment 6 is that the temperature of the reaction module is adjusted to 180° C., and the rest of the preparation process is the same as that of embodiment 1 to obtain a hydrogenated lecithin product.

[0083] Embodiment 11

[0084] This embodiment provides a method for preparing hydrogenated lecithin with 98%≤phosphatidylcholine (PC), specifically:

[0085] (1) dissolving egg yolk lecithin with a PC content of 70% in a mixed solution of toluene:methanol (v:v) = 1:1 to prepare a reaction solution with a mass fraction of 20%;

[0086] (2) 1 mL / min of the reaction solution was pumped into the reaction module of the continuous flow microreactor. The reaction module was cylindrical, with an inner diameter of 5 mm and a length of 50 mm, and was filled with 15 g of alumina-supported Pt catalyst (Pt content of 0.5%, Pt average particle size of 3.0 nm). The reaction module temperature was 150°C, the pressure was 3 MPa, and the residence time was 1 min;

[0087] (3) The reacted material enters a gas-liquid separator for cooling. The reaction solution is concentrated and dried to obtain a crude hydrogenated lecithin product, which is separated by column chromatography. The separated product is recrystallized with a mixed solution of n-heptane: acetone = 1:1 to obtain a white hydrogenated lecithin product. The HPLC results are shown in Figure 4 , PC content ≥98%, iodine value 2.0.

[0088] The products obtained in the above examples were tested, and the comparison results with those in Example 8 are shown in Table 4.

[0089] Table 4

[0090] Example 8 Example 9 Example 10 Embodiment 11 Iodine value 1.7 5.1 15 2 PC content (%) 82.7 71.2 70.9 >99

[0091] As can be seen from the above table, adjusting the temperature of the reaction module has a significant effect on the iodine value and PC content of the product. When the reaction temperature is too low, lecithin can only undergo hydrogen transfer reduction reaction, which can obtain a better product iodine value, but lecithin PE cannot be methylated, and the product PC content is still about 70%; when the reaction temperature is too high, methanol side reactions become more, on the one hand, CO is generated, which poisons the catalyst and makes the hydrogen transfer reduction reaction effect worse, and on the other hand, the reaction cannot obtain a higher concentration of formaldehyde, and cephalin PE cannot be methylated, so the product PC content is still about 70%. According to the results in the above table, for the preparation of hydrogenated lecithin products with 80%≤phosphatidylcholine (PC)≤98%, the best technical effect can be obtained when the temperature of the reaction module is 150°C.

[0092] Example 11 shows that column chromatography separation can further purify hydrogenated lecithin so that the PC content of the prepared hydrogenated lecithin product is >99%.

[0093] Comparative Example 1

[0094] (1) 1.0 g of soybean lecithin with a PC content of 20% and an iodine value of 79.0, 10 mL of toluene, and 50 mg of Pt / Al2O3 catalyst were added to a 25 mL reactor and reacted at 110°C for 10 h in a 3.0 MPa hydrogen atmosphere.

[0095] (3) After the reaction, the temperature is cooled, the catalyst is separated by centrifugation, and the reaction solution is concentrated and dried to obtain a crude hydrogenated lecithin product, which is then slurried with a methanol:acetone = 1:1 mixed solution to obtain a light yellow hydrogenated lecithin product.

[0096] Comparative Example 2

[0097] The difference between this comparative example and comparative example 1 is that the temperature of the reaction module is adjusted to 150° C., and the rest of the preparation process is the same as that of comparative example 1 to obtain a hydrogenated lecithin product.

[0098] The product obtained in the above comparative example was tested, and the comparison results with those of Example 1 are shown in Table 5.

[0099] Table 5

[0100] Example 1 Comparative Example 1 Comparative Example 2 Iodine value 5 10 23 PC content (%) 23.4 20.1 21.5

[0101] It can be seen from the above table that when hydrogen is used as the hydrogen source, the iodine value and PC content of the obtained hydrogenated lecithin do not reach the effect of Example 1; when the reaction temperature is increased to 150° C., hydrogenated lecithin with better PC content and iodine value cannot be obtained.

[0102] In summary, the present invention overcomes the defects of traditional hydrogenation reactions, uses methanol as a raw material, on the one hand as a green hydrogen source for hydrogenation, and on the other hand as a methyl source, to convert lecithin PE in the raw material into phosphatidylcholine PC, so that the PC content in the product becomes higher, and realizes the preparation of hydrogenated lecithin products with phosphatidylcholine PC contents of ≥20%, ≥80% and ≥98% respectively using lecithin as a raw material, while reducing the liquid holding capacity of the reaction system while improving the reaction efficiency, fundamentally reducing the process risk, and meeting different market demands.

[0103] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A continuous flow preparation process for hydrogenated lecithin with different phosphatidylcholine contents, characterized in that: include, Lecithin is dissolved in a solvent, and the resulting reaction solution is continuously pumped into a micro-packed bed reaction module filled with a hydrogen transfer reduction catalyst, where methylation and catalytic hydrogen transfer reduction reactions are performed under the action of the catalyst; The reacted material is cooled and concentrated to obtain crude hydrogenated lecithin, which is then pulped and purified to obtain hydrogenated lecithin.

2. The continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents as claimed in claim 1, characterized in that: The lecithin includes one or more of soybean lecithin, rapeseed lecithin or egg yolk lecithin; The lecithin is selected according to the PC content of the target product; When the PC content of the target product is 20% to 80%, the PC content of the lecithin is 20% to 35%; When the PC content of the target product is ≥80%, the PC content of the lecithin is 70% to 75%.

3. The continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents as claimed in claim 1, characterized in that: The solvent includes one or more of methanol, ethanol, isopropanol, dichloromethane, n-hexane, n-heptane, toluene, and chlorobenzene.

4. The continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents as claimed in claim 1, characterized in that: The mass fraction of lecithin in the reaction solution is 10% to 50%.

5. The continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents as claimed in claim 1, characterized in that: The pumping speed of the reaction solution is 0.3-2.0 mL / min.

6. The continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents as claimed in claim 1, characterized in that: The loading amount of the hydrogen transfer reduction catalyst is 15 to 20 g; the hydrogen transfer reduction catalyst is a supported nano metal catalyst with a metal loading of 0.1 to 5.0 wt%, the carrier of the supported nano metal catalyst includes one of aluminum oxide, silicon oxide, zinc oxide, cerium oxide, titanium oxide, magnesium oxide, and zirconium oxide; the active metal supported by the supported nano metal catalyst includes one of Pt, Ir, Ru, and Pd; and the average particle size of the active metal is 1 to 20 nm.

7. The continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents as claimed in claim 5, characterized in that: The micro-packed bed reaction module is cylindrical, the hydrogen transfer reduction catalyst fills the internal space of the micro-packed bed reaction module, and the reaction liquid flows along the axial direction of the micro-packed bed reaction module; wherein the aspect ratio of the micro-packed bed reaction module is 10 to 60:1, and the ratio of the inner diameter of the micro-packed bed reaction module to the average particle size of the hydrogen transfer reduction catalyst is 15 to 30:

1.

8. The continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents as claimed in claim 1, characterized in that: The temperature of the reaction module is selected according to the PC content of the target product; When the PC content of the target product is 20% to 80%, the temperature of the reaction module is 80° C. to 120° C.; When the PC content of the target product is ≥80%, the temperature of the reaction module is 120°C to 180°C; The reaction time is 30 to 600 seconds.

9. The continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents as claimed in claim 1, characterized in that: The slurrying solvent includes one or more of methanol, ethanol, isopropanol, dichloromethane, n-hexane, n-heptane, acetone and toluene.

10. The continuous flow preparation process of hydrogenated lecithin with different phosphatidylcholine contents as claimed in claim 1, characterized in that: The purification conditions are recrystallization or column chromatography; wherein the recrystallization solvent includes one or more of methanol, ethanol, isopropanol, dichloromethane, n-hexane, n-heptane, acetone, and toluene; and the column chromatography solvent includes one or more of petroleum ether, dichloromethane, n-hexane, n-heptane, and toluene.

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