Process for catalytically synthesizing ascorbyl tetraisopalmitate through biological enzyme

Abstract

The invention belongs to the technical field of organic synthesis, and particularly relates to a process for catalytically synthesizing ascorbyl tetraisopalmitate by a biological enzyme. The synthesis process comprises the following steps: attaching a biological enzyme to a metal organic framework compound material (MOFs material) to prepare biological enzyme catalyst powder, and adding a small amount of biological enzyme catalyst powder into methyl n-hexylcaprate and ascorbic acid which are used as raw materials for transesterification to prepare ascorbyl tetraisopalmitate. The process route is simple, few three wastes are generated, compared with a traditional preparation process of tetra-isopalm ascorbate, the yield and purity of the product are greatly improved, and experimental results show that the highest yield of the product is 89%, and the purity of the product reaches 99.0%.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, and specifically relates to a process for the bio-enzymatic synthesis of ascorbic acid tetraisopalmitate. Background Technology

[0002] Ascorbate tetraisopalmitate, or "VCIP" for short, is a vitamin C derivative. Vitamin C is a natural antioxidant widely used topically and orally to treat skin conditions, such as for its antioxidant, anti-inflammatory, photoprotective, anti-aging, and anti-pigmentation effects. However, vitamin C has poor skin penetration and is unstable in formulations. To overcome these shortcomings, researchers began exploring vitamin C derivatives. Ascorbate tetraisopalmitate is one of the commonly used vitamin C derivatives. Compared to vitamin C, ascorbate tetraisopalmitate has several longer-chain fatty acids in its structure. This structure makes it more lipophilic than vitamin C, allowing it to be directly absorbed through the skin, and it is also more stable than vitamin C.

[0003] Currently, many skincare brands have begun using tetraisopalmitate as a key ingredient, especially in the whitening and anti-aging fields. For example, some brands have launched a Brightening series featuring tetraisopalmitate as the main ingredient, covering a full range of products from cleansers to serums and creams, forming a relatively mature product line. Furthermore, by combining it with other whitening ingredients such as niacinamide and arbutin, the whitening effect of tetraisopalmitate has been further enhanced, making related products more competitive and attractive in the market.

[0004] Currently, the mainstream process for synthesizing ascorbic acid tetraisopalmitate is to first acylchlorinate n-hexyldecanoic acid and then esterify it with ascorbic acid to prepare the final product. Patents such as 201711102941.6 and 202211330946.5 both use this process. However, this synthesis method is difficult to operate, produces a lot of waste, and the controllability of the acyl chloride intermediate obtained in the reaction process is poor.

[0005] Patents 201811346692.X and 2021111642543.X, etc., all prepare ascorbic acid tetraisopalmitate by oxidative esterification of hexyldecaldehyde with ascorbic acid. The oxidation operation in the reaction process is difficult to control and has relatively many side reactions.

[0006] In addition, patents such as 202310354194.4 and 202411130554.3 disclose a method for preparing ascorbic acid tetraisopalmitate from methyl hexyldecanoate and ascorbic acid via transesterification. This reaction is reversible, but its efficiency is relatively low compared to other methods, and the reaction conditions are quite harsh. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes a process for the bio-enzymatic synthesis of ascorbic acid tetraisopalmitate. This process utilizes recyclable bio-enzymes as catalysts, making it more environmentally friendly and efficient compared to traditional strong alkaline catalysts. The synthesis process offers advantages such as reduced waste, simple operation, product yield exceeding 85%, and purity exceeding 98%. Furthermore, the reaction conditions are mild (no high temperature or high pressure required), and it can be achieved using conventional reagents and equipment, significantly improving safety and operability.

[0008] The technical solution of the present invention is as follows: First, bio-enzymes are attached to metal-organic framework compound materials (MOFs materials) to prepare bio-enzyme catalyst powder. Using methyl hexyldecanoate and ascorbic acid as raw materials, a small amount of bio-enzyme catalyst powder is added to carry out transesterification reaction to prepare ascorbic acid tetraisopalmitate.

[0009] The present invention proposes a process for the bio-enzymatic synthesis of ascorbate tetraisopalmitate, comprising the following steps: (1) Preparation of bio-enzyme catalysts: Bio-enzymes are prepared by immobilizing bio-enzymes on MOF materials; Among them, the biological enzyme is selected from any one of porcine pancreatic lipase, lipase MG10, Aspergillus niger lipase, and Burkholderia cepacia lipase. Preferably, the bioenzyme is selected from either porcine pancreatic lipase or lipase MG10; A further preferred option is porcine pancreatic lipase; MOF materials are selected from any one of UiO-66, MIL-53 (Al), and MIL-100 materials; Further preferred, the MOF material is UiO-66 material; The mass ratio of bio-enzyme to MOF material is 4:0.5-1.5; (2) Enzyme-catalyzed reaction: Methyl hexyldecanoate and ascorbic acid were added to reaction solvent I and the bio-enzyme catalyst prepared in (1) were reacted at a temperature of 40~60℃ and pH 2.5-4.0 for 24~48h; The molar ratio of methyl hexyldecanoate to ascorbic acid is 4-6:1, and the amount of biocatalyst used is 1-20% of the mass of ascorbic acid. (3) Purification: After the reaction is completed, the mixture is filtered to recover the bio-enzyme catalyst. The remaining filtrate is then distilled under reduced pressure to recover the solvent and obtain the final product, ascorbic acid tetraisopalmitate.

[0010] Preferably, in (1), the step of preparing the bio-enzyme catalyst is as follows: Take the bio-enzyme and add reaction solvent II, wherein reaction solvent II is selected from any one of glutaraldehyde, dimethyl sulfoxide, methanol, and ethanol. Add MOF material at 5~40℃, soak and stir for 1-2 hours, centrifuge and dry to obtain bio-enzyme catalyst powder.

[0011] Preferably, in (2), the reaction solvent I is selected from any one of methanol, ethanol, n-hexane, n-heptane, and petroleum ether, and the mass ratio of reaction solvent I to methyl hexyldecanoate is 2:1.

[0012] Preferably, in (3), the conditions for vacuum distillation are: temperature of 60℃ and pressure of -0.9MPa.

[0013] The process for synthesizing ascorbate tetraisopalmitate catalyzed by porcine pancreatic lipase includes the following steps: (1) Preparation of bio-enzyme catalyst: Take 100g of porcine pancreatic lipase, add 300g of methanol, stir and heat to 40℃, add 25g of UiO-66 material, soak and stir for 2h, centrifuge and dry to obtain bio-enzyme catalyst powder; (2) Enzyme-catalyzed reaction: Take 5g of porcine pancreatic lipase catalyst powder obtained in (1), add 600g of n-hexane, stir and heat to 40℃, add 306.62g of n-hexyldecanoate methyl ester and 50g of ascorbic acid, adjust the pH to 3.0, and react for 48h; (3) Purification: After the reaction is completed, filter and recover the porcine pancreatic lipase catalyst powder. It can be recycled 3-5 times. The filtrate is washed with water 2-3 times. After washing, it is distilled under reduced pressure at 60℃ and -0.9MPa to recover the solvent n-hexane. After distillation, the final product ascorbic acid tetraisopalmitate is obtained.

[0014] The present invention has the following advantages and effects compared with the prior art: (1) The present invention uses biological enzymes as catalysts, which can be reused repeatedly. Compared with other strong alkaline catalysts used in transesterification reactions, it is more environmentally friendly and has a higher utilization rate. (2) Compared with other processes, the process provided by the present invention has relatively less waste, is relatively simple to operate, and has a total product yield of over 85% and a purity of over 98.0%. (3) The entire synthesis process of the present invention does not involve high pressure or high temperature. The raw materials and solvents used in the process are all conventional reagents, which are highly safe and operable. The reaction can be carried out in a conventional reaction vessel. Attached Figure Description

[0015] Figure 1 This is a high-performance liquid chromatogram of the target product after purification by the process in Example 1 of the present invention; Figure 2This is a high-performance liquid chromatogram of the target product purified by the process in Comparative Example 3 of this invention. Figure 3 This is a high-performance liquid chromatogram of the target product purified by the process in Comparative Example 4 of this invention. Figure 4 This is a high-performance liquid chromatogram of the target product after purification by the process of Comparative Example 10 of this invention. Detailed Implementation

[0016] To enable those skilled in the art to better understand the present invention, the present invention will now be further described in conjunction with specific embodiments.

[0017] Example 1: A process for the bio-enzymatic synthesis of ascorbic acid tetraisopalmitate includes the following steps: (1) Preparation of bio-enzyme catalyst: Add 100g of porcine pancreatic lipase and 300g of methanol to the reaction flask, stir and heat to 40℃, add 25g of UiO-66 material, soak and stir for 2h, centrifuge and dry to obtain bio-enzyme catalyst powder. (2) Enzyme-catalyzed reaction: Take 5g of the bio-enzyme catalyst obtained in (1) and add it to a 2000 mL three-necked flask. Add 600g of n-hexane, stir and heat to 40℃, add 306.62g of n-hexyldecanoate methyl ester and 50g of ascorbic acid, pH 3.0, react for 48h, and test. If the purity of the sample is above 98%, it is considered qualified. (3) Purification: After passing the test, the reaction ends, the filter is used, the bio-enzyme catalyst is recovered, the filtrate is washed with water 2-3 times, and after washing, it is distilled under reduced pressure at a temperature of 60℃ and a pressure of -0.9MPa to recover the solvent. After distillation, the final product ascorbic acid tetraisopalmitate is obtained.

[0018] Detected by high performance liquid chromatography, such as Figure 1 As shown, the yield of the final product ascorbate tetraisopalmitate obtained in this embodiment was 89%, and the purity was 99.0%.

[0019] Example 2: The difference from Example 1 is that in (1), the reaction time was reduced to 1 hour, while other process conditions were exactly the same as in Example 1. The yield of the target product was tested to be 85.5%, and the purity was 98.0%.

[0020] Example 3: The only difference from Example 1 is that the condensation reaction temperature in (1) is 5°C. All other process conditions are exactly the same as in Example 1. The yield of the target product was found to be 85.0%, and the product purity was 98.5%.

[0021] Example 4: The only difference from Example 1 is that in (2), the molar ratio of ascorbic acid to methyl hexyldecanoate is 1:6. The yield of the target product was tested to be 87.0%, and the purity was 98.6%.

[0022] Example 5: The only difference from Example 1 is that the reaction temperature in (2) is 60°C. The yield of the target product was tested to be 86.1%, and the purity was 98.9%.

[0023] Example 6: The only difference from Example 1 is that the reaction time in (2) is 24 hours. The yield of the target product was found to be 85.0%, and the purity was 98.4%.

[0024] Experimental Example 1: Screening of biological enzymes The same process as in Example 1 was used, except that the biological enzymes in (1) were different. Different biological enzymes (porcine pancreatic lipase, lipase MG10, Aspergillus niger lipase, Burkholderia cepacia lipase) were selected for experimental verification. The specific experimental results are shown in Table 1 below.

[0025] Table 1 Comparison of catalytic results of various biological enzymes Serial Number Biological enzymes Product yield purity 1 porcine pancreatic lipase ≥85% ≥98% 2 Lipase MG10 75%~80% ≥96% 3 Aspergillus niger lipase 60%~70% ≥91% 4 Burkholderia cepacia lipase 65%~70% ≥93%

[0026] Experimental Example 2: Screening of MOF Materials The same process as in Example 1 was used, with the only difference being that: (1) the MOFs materials on which the bio-enzyme was attached were different. Different MOFs materials (UiO-66 material, MIL-53 (Al) material, MIL-100 material) were selected for the experiment, and the specific experimental results are shown in Table 2 below: Table 2 Comparison of experimental results for various MOF materials Serial Number MOFs materials MOFs bioenzyme performance 1 UiO-66 material The catalytic efficiency reached 83.0% after 5 cycles of testing. 2 MIL-53 (Al) material The catalytic efficiency reached 78.6% after 5 cycles of testing. 3 MIL-100 material The catalytic efficiency reached 66.3% after 5 cycles of testing.

[0027] Comparative Example 1 The same synthesis process as in Example 1 was used, except that the reaction time in (1) was 0.5 h. The yield of the target product was 75.0%, and the purity was 98.5%.

[0028] Comparative Example 2 The same synthesis process as in Example 1 was used, except that the reaction time in (1) was 2.5 h. The yield of the target product was 77.5%, and the purity was 97.9%.

[0029] Comparative Example 3 The synthesis process was exactly the same as in Example 1, except that the reaction temperature in (2) was 35°C. Upon testing, as shown... Figure 2 As shown, the yield of the target product was 71.0%, and the purity of the product was 97.3%.

[0030] Comparative Example 4 The synthesis process was exactly the same as in Example 1, except that the reaction temperature in (2) was 65°C. Upon testing, as shown... Figure 3 As shown, the yield of the target product was 72.0%, and the purity of the product was 98.0%.

[0031] Comparative Example 5 The same synthesis process as in Example 1 was used, except that the molar ratio of ascorbic acid to methyl hexyldecanoate in (2) was 1:3. The yield of the target product obtained by using the process of this comparative example was 60.0%, and the purity of the product was 95.9%.

[0032] Comparative Example 6 The same synthesis process as in Example 1 was used, except that the molar ratio of ascorbic acid to methyl hexyldecanoate in (2) was 1:7. The yield of the target product was 77.0%, and the purity was 98.0%.

[0033] Comparative Example 7 The same synthesis process as in Example 1 was used, except that the mass ratio of the bioenzyme to the MOF material in (1) was 0.9:1. The yield of the target product was 71.0%, and the purity was 97.9%.

[0034] Comparative Example 8 The same synthesis process as in Example 1 was used, except that: (1) the mass ratio of bioenzyme to MOF material was 5:1. The yield of the target product was 85.1% and the purity of the product was 98.5%.

[0035] Comparative Example 9 The synthesis method was the same as in Example 1, except that in (2), the reaction time was extended to 23 hours. The yield of the target product was 75.0%, and the purity was 97.4%.

[0036] Comparative Example 10 Ascorbic acid tetraisopalmitate was prepared using traditional methods, namely, methyl hexyldecanoate and ascorbic acid as raw materials, with a basic catalyst for catalytic reaction, followed by methanol extraction, washing with water, concentration by column chromatography, and vacuum concentration to obtain the final product. The specific synthesis method is as follows: At room temperature, 880 g of n-hexane was added to a 2 L four-necked flask. While stirring, 88 g of ascorbic acid (500 mmol), 24.88 g of dibutyltin oxide (100 mmol), and 567.56 g of methyl 2-hexyldecanoate (2.1 mol) were added in portions. After stirring for 10 min, the mixture was heated to reflux and reacted at this temperature for 8 h. After the reaction was complete, the mixture was cooled to room temperature, and 220 g of methanol was added for extraction twice. 220 g of water was added for washing twice. Then, 70 g of anhydrous magnesium sulfate was added, and the mixture was stirred for 30 min before filtration to remove the anhydrous magnesium sulfate. Next, 30 g of activated carbon was added, and the mixture was stirred for 30 min before filtration to remove the activated carbon. After concentration, column purification was performed (eluent ratio: petroleum ether: n-hexane = 1:20). The eluted and concentrated liquid yielded a colorless, transparent liquid. Analysis showed that... Figure 4 As shown, the product yield was 65.0% and the purity was 98.1%.

[0037] To more clearly compare the effects of various process parameters on the yield and purity of the target product in this invention, the yield and purity of the target products obtained in Examples 1-6 and Comparative Examples 1-10 of this invention are listed again in Table 3 below.

[0038] Table 3. Yield and purity of the target product under different process conditions experimental group yield purity Example 1 89.0% 99.0% Example 2 85.5% 98.0% Example 3 85.0% 98.5% Example 4 87.0% 98.6% Example 5 86.1% 98.9% Example 6 85.0% 98.4% Comparative Example 1 75.0% 98.5% Comparative Example 2 77.5% 97.9% Comparative Example 3 71.0% 97.3% Comparative Example 4 72.0% 98.0% Comparative Example 5 60.0% 95.9% Comparative Example 6 77.0% 98.0% Comparative Example 7 71.0% 97.9% Comparative Example 8 85.1% 98.5% Comparative Example 9 75.0% 97.4% Comparative Example 10 65.0% 98.1%

[0039] As can be seen from the results in Table 3, the process of the present invention can successfully prepare the target product under certain conditions. However, only under the process conditions and parameters of Example 1, the total yield and purity of the prepared ascorbic acid tetraisopalmitic acid are the highest. In particular, the yield of the product is as high as 89%, which is 24 percentage points higher than the total yield of 65% of the product prepared by the conventional method in Comparative Example 10.

[0040] Furthermore, the experimental results of the various embodiments and comparative examples of the present invention show that, in the process of preparing ascorbic acid tetraisopalmitic acid, the solvent used, the molar ratio between raw materials, and the temperature and time control of the reaction process all have a significant impact on the product yield.

[0041] Examples 2, 1, and 2 optimized the reaction time in step (1). The results were not significantly different between reactions with a reaction time exceeding 2 hours and those with a reaction time of 2 hours. However, when the reaction time was less than 1 hour, the yield of the catalytic reaction was less than 80%. Example 4, Comparative Example 3 and Comparative Example 4 optimized the molar ratio of ascorbic acid to methyl hexyldecanoate in reaction step (2). When the molar ratio was less than 1:4, the reaction was incomplete, which led to a decrease in yield. When it was greater than 1:6, the reaction byproducts increased and the product purity decreased.

[0042] Example 5, Comparative Example 3 and Comparative Example 4 optimized the temperature of step (2). When the temperature is below 40°C, the reaction is incomplete and the reaction yield is low. When the temperature is above 60°C, the reaction by-products increase and the purity decreases.

[0043] In addition to the bio-enzyme catalyst provided in this invention, its synthesis process parameters are also a key technical point of this invention. Only within the range defined by the process parameters of this invention can a target product with high yield and purity be obtained.

[0044] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. All equivalent changes and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A process for the synthesis of ascorbic acid tetraisopalmitate catalyzed by a biological enzyme, characterized in that, The steps include the following: (1) Preparation of a biological enzyme catalyst: biological enzymes are immobilized on metal organic framework compound materials as catalysts to prepare a biological enzyme catalyst; Wherein the biological enzyme is selected from any one of porcine pancreatic lipase, lipase MG10, Aspergillus niger lipase, and Burkholderia cepacia lipase; The metal organic framework compound material is selected from any one of UiO-66 material, MIL-53 (Al) material, and MIL-100 material; The mass ratio of biological enzyme to metal organic framework compound material is 4:0.5-1.5; (2) Enzymatic catalytic reaction: using n-hexyl capric acid methyl ester and ascorbic acid as raw materials, adding reaction solvent I and the biological enzyme catalyst prepared in (1), and reacting at a temperature of 40-60℃ and a pH of 2.5-4.0 for 24-48h; Wherein the molar ratio of n-hexyl capric acid methyl ester to ascorbic acid is 4-6:1, and the amount of biological catalyst is 1-20% of the mass of ascorbic acid; (3) Impurity removal and purification: after the reaction is completed, the biological enzyme catalyst is recovered by filtration, and the remaining filtrate is distilled under reduced pressure to recover the solvent, and the final product ascorbic acid tetraisopalmityl ester is obtained.

2. The process for biosynthetic catalysis of ascorbic acid tetraisopalmitate according to claim 1, characterized in that, In (1), the step of preparing the biological enzyme catalyst is: Take the biological enzyme, add reaction solvent II, wherein reaction solvent II is selected from any one of glutaraldehyde, dimethyl sulfoxide, methanol, and ethanol, add metal organic framework compound material at 5-40℃, soak and stir for 1-2h, centrifuge and dry to obtain biological enzyme catalyst powder.

3. The process for synthesis of ascorbic acid tetraisopalmitate catalyzed by biological enzyme according to claim 1, characterized in that, In (2), the reaction solvent I is selected from any one of methanol, ethanol, n-hexane, n-heptane, and petroleum ether, and the mass ratio of reaction solvent I to n-hexyl capric acid methyl ester is 2:

1.

4. The process for biosynthetic catalysis of ascorbic acid tetraisopalmitate according to claim 1, characterized in that, In (3), the conditions for reduced pressure distillation are: temperature 60℃, pressure-0.9MPa.

5. The process for synthesizing ascorbic acid tetraisopalmityl ester catalyzed by porcine pancreatic lipase includes the following steps: (1) Preparation of a biological enzyme catalyst: take 100g of porcine pancreatic lipase, add 300g of methanol, stir and warm to 40℃, add 25g of UiO-66 material, soak and stir for 2h, centrifuge and dry to obtain porcine pancreatic lipase catalyst powder; (2) Enzymatic catalytic reaction: take 5g of porcine pancreatic lipase catalyst powder obtained in (1), add 600g of n-hexane, stir and warm to 40℃, add 306.62g of n-hexyl capric acid methyl ester and 50g of ascorbic acid, adjust the pH to 3.0, and react for 48h; (3) Impurity removal and purification: after the reaction is completed, filter to recover the porcine pancreatic lipase catalyst powder, wash the filtrate with water 2-3 times, distill under reduced pressure at a temperature of 60℃ and a pressure of-0.9MPa after water washing to recover the solvent n-hexane, and obtain the final product ascorbic acid tetraisopalmityl ester after distillation.

6. The process as claimed in claim 5, wherein, In (3), the recovered porcine pancreatic lipase catalyst powder is recycled for 3-5 times.

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