Preparation method of vitamin C ethyl ether

Abstract

The invention relates to the field of vitamin C derivatives, in particular to a preparation method of vitamin C ethyl ether, which comprises the following steps: step 1, preparing an intermediate I from vitamin C and 2, 2-dimethoxypropane under the catalytic action of perfluorosulfonic acid resin; step 2, adding the intermediate I and bromoethane into an organic solvent, then adding an acid-binding agent and a catalyst sodium bromide, and reacting to obtain an intermediate II; and step 3, adding an alcohol solvent into the intermediate II, adding the catalyst separated in the step 2, dropwise adding glacial acetic acid, and synthesizing to obtain the vitamin C diethyl ether. According to the method, two recoverable catalysts are used, and the vitamin C diethyl ether is obtained through reaction, so that the reaction time is greatly shortened, few byproducts are produced, the yield is high, and the product purity is higher.

Description

Technical Field

[0001] The present invention relates to the field of vitamin C derivatives, and particularly to a method for preparing vitamin C ethyl ether. Background Art

[0002] Vitamin C is one of the strongest antioxidants in nature. It can capture free radicals, protect cell tissues, and resist the damage caused by free radicals and reactive oxygen species. Due to the disadvantages of vitamin C such as low lipophilicity, thermosensitivity, and self-oxidative degradation, its application is limited. Therefore, many vitamin C derivatives that improve its performance have emerged, such as magnesium ascorbyl phosphate and ascorbyl palmitate that have been widely used. Vitamin C ethyl ether is a new amphiphilic vitamin C derivative with both lipophilic and hydrophilic properties. It can be used very conveniently in formulations, easily penetrate the stratum corneum of the skin and enter the dermis layer. After entering the skin, it is easily decomposed by biological enzymes to exert the biological effects of vitamin C, thereby improving its bioavailability. Therefore, it can be used as an anti-aging agent and a whitening agent in cosmetics.

[0003] Currently, the commonly used process for synthesizing vitamin C ethyl ether on the market is usually a three-step method. The three-step synthesis method is that vitamin C first reacts with acetone under the catalysis of an acid to form 5,6-O-isopropylidene-ascorbic acid, then reacts with a halogenated alkane or diethyl sulfate to form an ether, and finally the ketal is hydrolyzed under the catalysis of an acid to produce vitamin C ethyl ether. In the above synthesis process, the first reaction requires the use of an acid catalyst that cannot be recycled, and the commonly used acids are acetyl chloride, p-toluenesulfonic acid, concentrated sulfuric acid, concentrated hydrochloric acid, etc.; in the second reaction, sodium bicarbonate, potassium carbonate, potassium bicarbonate, etc. are usually used as acid acceptors. The reaction temperature is relatively high, the reaction time is too long, and there are more disubstituted products, and the yield is also relatively low; in the third reaction, an organic solvent is usually used for hydrolysis under acidic conditions, the amount of water used in the reaction is large, and it is difficult to remove water during post-treatment, which is not conducive to product crystallization.

[0004] Therefore, the problems existing in the existing process for synthesizing vitamin C ethyl ether are that the synthesis efficiency is not high, and there are more by-products generated. In addition, the purity of the obtained product is relatively low. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a method for preparing vitamin C ethyl ether.

[0006] The purpose of the present invention is achieved by adopting the following technical solutions:

[0007] A method for preparing vitamin C ethyl ether, comprising the following steps:

[0008] Step 1, Weigh vitamin C and 2,2-dimethoxypropane and add them to the first organic solvent. After stirring well, add the first catalyst. After catalytic treatment, perform solid-liquid separation. After rotary evaporation to remove methanol and the solvent from the separated liquid, intermediate I is obtained;

[0009] Step 2, Add intermediate I and bromoethane to the second organic solvent, then add an acid-binding agent and the second catalyst, and raise the temperature for reaction. After the reaction is completed, rotary evaporate to dryness, and then after extraction, washing, and drying, separate the second catalyst and obtain intermediate II;

[0010] Step 3, Add to intermediate II an alcohol solvent, add the second catalyst separated in Step 2, and then dropwise add glacial acetic acid. After heating for reaction and purification, vitamin C ethyl ether is synthesized.

[0011] Preferably, in Step 1, the reaction temperature is 25 - 35 °C and the reaction time is 1 - 4 h.

[0012] Preferably, in Step 1, the mass-volume ratio of vitamin C, 2,2-dimethoxypropane, and the first solvent is (1.7 - 3.4) g : (1.5 - 3) g : (10 - 20) mL.

[0013] Preferably, in Step 1, the first solvent is one or more of acetone, tetrahydrofuran, dichloromethane, and acetonitrile.

[0014] Preferably, in Step 1, the first catalyst is perfluorosulfonic acid resin, and the addition amount of the first catalyst is 2% - 6% of the mass of vitamin C.

[0015] Preferably, in Step 2, the second solvent is one or more of carbon tetrachloride, toluene, xylene, dimethyl sulfoxide, and N,N-dimethylformamide.

[0016] Preferably, in Step 2, the reaction temperature is 30 - 40 °C and the reaction time is 6 - 12 h.

[0017] Preferably, in Step 2, the addition amount of bromoethane is 0.7 - 1.1 times the mass of vitamin C, and the addition amount of the second solvent is 4 - 6 times the volume of bromoethane.

[0018] Preferably, in Step 2, the second catalyst is sodium bromide, and the addition amount is 1.5% - 5.5% of the mass of vitamin C.

[0019] Preferably, in Step 2, the acid-binding agent is triethylamine, and the addition amount is 0.6 - 0.9 times the mass of vitamin C.

[0020] Specifically, in Step 2, extraction is performed using a mixed solution of ethyl acetate and deionized water; washing is performed using saturated saline; drying is performed under vacuum.

[0021] Specifically, in Step 3, the reaction temperature is 55 - 75 °C, and the reaction time is 0.2 - 0.6 h.

[0022] Specifically, in Step 3, the addition amount of the second catalyst separated in Step 2 is 1% - 4% of the mass of vitamin C.

[0023] Specifically, in Step 3, the addition amount of glacial acetic acid is 1% - 5% of the mass of vitamin C.

[0024] Specifically, in Step 3, the alcohol solvent is methanol or ethanol, and the volume of the alcohol solvent is 5 - 15 mL.

[0025] Specifically, in Step 3, the purification method is one of low-temperature (0 - 5 °C) crystallization, recrystallization, and nanofiltration membrane.

[0026] The beneficial effects of the present invention are as follows:

[0027] 1. The present invention provides a new synthetic preparation process for the cosmetic whitening and antioxidant vitamin C ethyl ether. Different from the conventional synthetic process, the present invention uses two recoverable catalysts. The vitamin C ethyl ether obtained through the reaction not only significantly shortens the reaction time, but also has fewer by-products, a high yield, and a higher product purity.

[0028] 2. In the first-step reaction for preparing vitamin C ethyl ether, vitamin C and 2,2-dimethoxypropane react under the action of recoverable perfluorosulfonic acid resin to synthesize the acetone-protected vitamin C ethyl ether intermediate I. This reaction process is relatively fast, and the catalyst can be recovered and reused, which is more environmentally friendly.

[0029] 3. In the second-step reaction for preparing vitamin C ethyl ether, intermediate I and bromoethane react in an organic solvent with triethylamine as an acid-binding agent and LiBr added as a catalyst to synthesize intermediate II. In this process, what differentiates the present invention from the conventional reaction is the addition of LiBr as a catalyst, which not only significantly shortens the reaction time of this step (the traditional second step requires 18 - 24 h), but also the catalyst can be recovered and continued to be applied in the third-step reaction.

[0030] 4. In the third-step reaction for preparing vitamin C ethyl ether, intermediate II uses the sodium bromide and glacial acetic acid recovered from the second-step reaction as catalysts to finally synthesize vitamin C ethyl ether in a high yield. Description of the Drawings

[0031] The present invention will be further described with reference to the accompanying drawings. However, the embodiments in the drawings do not constitute any limitation to the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the following drawings without creative work.

[0032] Figure 1 It is a schematic diagram of high performance liquid chromatography of Intermediate II obtained in the process of preparing vitamin C ethyl ether in Example 1 of the present invention;

[0033] Figure 2 It is a schematic diagram of high performance liquid chromatography of the product vitamin C ethyl ether obtained in the process of preparing vitamin C ethyl ether in Example 1 of the present invention. Detailed implementation manners

[0034] In order to better understand the above technical solutions, the exemplary embodiments of the present invention will be described in more detail below. Although the exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present invention can be more thoroughly understood and the scope of the present invention can be fully conveyed to those skilled in the art.

[0035] The present invention will be further described in conjunction with the following embodiments.

[0036] Example 1

[0037] A preparation method of vitamin C ethyl ether, comprising the following steps:

[0038] Step 1, weigh 2.5 g of vitamin C (L-ascorbic acid) and 2.3 g of 2,2-dimethoxypropane, add them to 15 mL of acetonitrile, stir well, add perfluorosulfonic acid resin DHS103, and the addition amount is 4% of the mass of vitamin C. After catalytic treatment at 30 °C for 2.5 h, perform solid-liquid separation. After the separated liquid is rotary evaporated to remove methanol and the solvent, Intermediate I is obtained;

[0039] Step 2, add Intermediate I and bromoethane to N,N-dimethylformamide. The addition amount of bromoethane is 0.9 times the mass of vitamin C, and N,N-dimethylformamide is 5 times the volume of bromoethane; then add triethylamine, and the addition amount is 0.7 times the mass of vitamin C; at the same time, add sodium bromide, and the addition amount is 3.5% of the mass of vitamin C; heat up to 35 °C and react for 9 h. After the reaction is completed, rotary evaporate to dryness, extract 3 times with a mixed solution of ethyl acetate and deionized water with a volume ratio of 2:1. The collected aqueous phase is dried to obtain sodium bromide, and the collected organic phase is washed three times with saturated brine and dried in vacuum to obtain Intermediate II; the spectrum of Intermediate II is detected by high performance liquid chromatography (HPLC) as Figure 1 shown;

[0040] Step 3: Add 10 mL of methanol to Intermediate II, add the second catalyst separated in Step 2, with the addition amount being 3% of the mass of vitamin C. Then, add glacial acetic acid with an amount of 3% of the mass of vitamin C dropwise. After heating to 65 °C, react for 0.4 h. After concentration under reduced pressure, crystallize at low temperature (0 - 5 °C) to synthesize vitamin C ethyl ether. The chromatogram of the product detected by high performance liquid chromatography (HPLC) is as Figure 2 shown.

[0041] Example 2

[0042] A preparation method of vitamin C ethyl ether, comprising the following steps:

[0043] Step 1: Weigh 1.8 g of vitamin C (L-ascorbic acid) and 1.7 g of 2,2-dimethoxypropane, add them to 12 mL of acetone. After stirring well, add perfluorosulfonic acid resin DHS103, with the addition amount being 3% of the mass of vitamin C. After catalytic treatment at 25 °C for 2 h, perform solid-liquid separation. After rotary evaporation to remove methanol and the solvent from the separated liquid, Intermediate I is obtained;

[0044] Step 2: Add Intermediate I and bromoethane to dimethyl sulfoxide. The addition amount of bromoethane is 0.7 times the mass of vitamin C, and dimethyl sulfoxide is 4 times the volume of bromoethane. Then, add triethylamine, with the addition amount being 0.7 times the mass of vitamin C. At the same time, add sodium bromide, with the addition amount being 2.5% of the mass of vitamin C. Heat to 35 °C and react for 7 h. After the reaction ends, rotary evaporate to dryness, extract with a mixed solution of ethyl acetate and deionized water. Dry the collected aqueous phase to obtain sodium bromide, wash the collected organic phase three times with saturated brine, and dry under vacuum to obtain Intermediate II;

[0045] Step 3: Add 10 mL of methanol to Intermediate II, add the second catalyst separated in Step 2, with the addition amount being 2% of the mass of vitamin C. Then, add glacial acetic acid with an amount of 2% of the mass of vitamin C dropwise. After heating to 65 °C, react for 0.3 h. After concentration under reduced pressure, crystallize at low temperature (0 - 5 °C) to synthesize vitamin C ethyl ether.

[0046] Example 3

[0047] A preparation method of vitamin C ethyl ether, comprising the following steps:

[0048] Step 1: Weigh 2.1 g of vitamin C (L-ascorbic acid) and 1.8 g of 2,2-dimethoxypropane, add them to 15 mL of tetrahydrofuran. After stirring well, add perfluorosulfonic acid resin DHS103, with the addition amount being 4% of the mass of vitamin C. After catalytic treatment at 30 °C for 3 h, perform solid-liquid separation. After rotary evaporation to remove methanol and the solvent from the separated liquid, Intermediate I is obtained;

[0049] Step 2: Add intermediate I and bromoethane into N,N-dimethylformamide. The addition amount of bromoethane is 1.1 times the mass of vitamin C, and N,N-dimethylformamide is 6 times the volume of bromoethane. Then add triethylamine, with the addition amount being 0.7 times the mass of vitamin C. Meanwhile, add sodium bromide, with the addition amount being 3% of the mass of vitamin C. Heat up to 30°C and react for 8 h. After the reaction ends, rotary evaporate to dryness, extract with a mixed solution of ethyl acetate and deionized water, dry the collected aqueous phase to obtain sodium bromide, wash the collected organic phase three times with saturated brine, and dry under vacuum to obtain intermediate II;

[0050] Step 3: Add 7 mL of ethanol into intermediate II, add the second catalyst separated in Step 2, with the addition amount being 3% of the mass of vitamin C, then dropwise add glacial acetic acid with the addition amount being 2% of the mass of vitamin C. Heat up to 65°C and react for 0.4 h, then concentrate under reduced pressure and crystallize at low temperature (0 - 5°C) to synthesize vitamin C ethyl ether.

[0051] Example 4

[0052] A preparation method of vitamin C ethyl ether, comprising the following steps:

[0053] Step 1: Weigh 1.7 g of vitamin C (L-ascorbic acid) and 1.5 g of 2,2-dimethoxypropane, add them into 10 mL of dichloromethane, stir well, add perfluorosulfonic acid resin DHS103, with the addition amount being 2% of the mass of vitamin C. After catalytic treatment at 25°C for 1 h, perform solid-liquid separation. After rotary evaporating the separated liquid to remove methanol and the solvent, obtain intermediate I;

[0054] Step 2: Add intermediate I and bromoethane into N,N-dimethylformamide. The addition amount of bromoethane is 0.9 times the mass of vitamin C, and N,N-dimethylformamide is 5 times the volume of bromoethane. Then add triethylamine, with the addition amount being 0.6 times the mass of vitamin C. Meanwhile, add sodium bromide, with the addition amount being 1.5% of the mass of vitamin C. Heat up to 30°C and react for 6 h. After the reaction ends, rotary evaporate to dryness, extract with a mixed solution of ethyl acetate and deionized water, collect the organic phase, wash it three times with saturated brine, and dry under vacuum to obtain intermediate II;

[0055] Step 3: Add 5 mL of methanol into intermediate II, add the second catalyst separated in Step 2, with the addition amount being 1% of the mass of vitamin C, then dropwise add a small amount of glacial acetic acid, with the addition amount of glacial acetic acid being 1% of the mass of vitamin C. Heat up to 55°C and react for 0.2 h, then concentrate under reduced pressure and crystallize at low temperature (0 - 5°C) to synthesize vitamin C ethyl ether.

[0056] Example 5

[0057] A method for preparing vitamin C ethyl ether, comprising the following steps:

[0058] Step 1: Weigh 3.4 g of vitamin C (L-ascorbic acid) and 3 g of 2,2-dimethoxypropane, add them to 20 mL of toluene. After stirring well, add perfluorosulfonic acid resin DHS103, and the addition amount is 6% of the mass of vitamin C. After catalytic treatment at 35 °C for 4 h, carry out solid-liquid separation. After the separated liquid is rotary evaporated to remove methanol and the solvent, intermediate I is obtained;

[0059] Step 2: Add intermediate I and bromoethane to N,N-dimethylformamide. The addition amount of bromoethane is 0.9 times the mass of vitamin C, and N,N-dimethylformamide is 5 times the volume of bromoethane. Then add triethylamine, and the addition amount is 0.9 times the mass of vitamin C. At the same time, add sodium bromide, and the addition amount is 5.5% of the mass of vitamin C. Heat up to 40 °C and react for 12 h. After the reaction is completed, rotary evaporate to dryness, extract with a mixed solution of ethyl acetate and deionized water, collect the organic phase, wash it three times with saturated brine, and dry it under vacuum to obtain intermediate II;

[0060] Step 3: Add 15 mL of ethanol to intermediate II, add the second catalyst separated in step 2, and the addition amount is 4% of the mass of vitamin C. Then dropwise add a small amount of glacial acetic acid, and the addition amount of glacial acetic acid is 5% of the mass of vitamin C. Heat up to 75 °C and react for 0.6 h. After concentration under reduced pressure, crystallize at low temperature (0 - 5 °C) to synthesize vitamin C ethyl ether.

[0061] Comparative Example 1

[0062] A method for preparing vitamin C ethyl ether, which is different from Example 1 in that the catalyst in step 1 is replaced with hydrochloric acid of equal mass, no catalyst is added in step 2, and the catalyst in step 3 is replaced with hydrochloric acid of equal mass. Specifically:

[0063] Step 1: Weigh 2.5 g of vitamin C and 2.3 g of 2,2-dimethoxypropane, add them to 15 mL of acetonitrile. After stirring well, add 0.1 mol / L hydrochloric acid, and the addition amount is 4% of the mass of vitamin C. After catalytic treatment at 30 °C for 2.5 h, carry out solid-liquid separation. After the separated liquid is rotary evaporated to remove methanol and the solvent, intermediate I is obtained;

[0064] Step 2: Add intermediate I and bromoethane into N,N-dimethylformamide. The addition amount of bromoethane is 0.9 times the mass of vitamin C, and N,N-dimethylformamide is 5 times the volume of bromoethane. Then add triethylamine, and the addition amount is 0.7 times the mass of vitamin C. Heat up to 35 °C and react for 9 h. After the reaction ends, rotary evaporate to dryness, extract 3 times with a mixed solution of ethyl acetate and deionized water with a volume ratio of 2:1, collect the organic phase, wash it three times with saturated brine, and dry it under vacuum to obtain intermediate II;

[0065] Step 3: Add 10 mL of methanol into intermediate II, add 0.1 mol / L hydrochloric acid, and the addition amount is 3% of the mass of vitamin C. Then dropwise add glacial acetic acid with an amount of 3% of the mass of vitamin C. Heat up to 65 °C and react for 0.4 h. After concentration under reduced pressure, crystallize at low temperature (0 - 5 °C) to synthesize vitamin C ethyl ether.

[0066] Comparative Example 2

[0067] A preparation method of vitamin C ethyl ether, which is different from Example 1 in that the catalyst in Step 1 remains unchanged, no catalyst is added in Step 2, and the catalyst in Step 3 is replaced with hydrochloric acid of the same mass. Specifically:

[0068] Step 1: Weigh 2.5 g of vitamin C and 2.3 g of 2,2-dimethoxypropane, add them into 15 mL of acetonitrile, stir well, add perfluorosulfonic acid resin DHS103, and the addition amount is 4% of the mass of vitamin C. After catalytic treatment at 30 °C for 2.5 h, perform solid-liquid separation. After rotary evaporation of the separated liquid to remove methanol and the solvent, obtain intermediate I;

[0069] Step 2: Add intermediate I and bromoethane into N,N-dimethylformamide. The addition amount of bromoethane is 0.9 times the mass of vitamin C, and N,N-dimethylformamide is 5 times the volume of bromoethane. Then add triethylamine, and the addition amount is 0.7 times the mass of vitamin C. Heat up to 35 °C and react for 9 h. After the reaction ends, rotary evaporate to dryness, extract 3 times with a mixed solution of ethyl acetate and deionized water with a volume ratio of 2:1, collect the organic phase, wash it three times with saturated brine, and dry it under vacuum to obtain intermediate II;

[0070] Step 3: Add 10 mL of methanol into intermediate II, add 0.1 mol / L hydrochloric acid, and the addition amount is 3% of the mass of vitamin C. Then dropwise add glacial acetic acid with an amount of 3% of the mass of vitamin C. Heat up to 65 °C and react for 0.4 h. After concentration under reduced pressure, crystallize at low temperature (0 - 5 °C) to synthesize vitamin C ethyl ether.

[0071] The yields and purities of the vitamin C ethyl ether prepared in Example 1, Comparative Example 1 and Comparative Example 2 were detected respectively, and the results are shown in Table 1:

[0072] Table 1 Detection Results of Ethyl Ascorbic Acid

[0073] Example 1 Comparative Example 1 Comparative Example 2 Yield (%) 95.8 78.3 82.5 Purity (%) 99.6 90.1 93.3

[0074] It can be seen from the detection results in Table 1 that the yield of the ethyl ascorbic acid prepared in Example 1 of the present invention is as high as 95.8%, and the purity is as high as 99.6%. While the yields of Comparative Examples 1-2 are about 80%, and the purities are also much lower than that of Example 1. This shows that the method of Example 1 can make the reaction of the reactants more complete with fewer by-products. Under the same reaction conditions, both the yield and the purity are significantly improved compared with the comparative examples.

[0075] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0076] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A preparation method of vitamin C ethyl ether, characterized in that, It includes the following steps: Step 1: Weigh vitamin C and 2,2-dimethoxypropane and add them to the first organic solvent. After stirring evenly, add the first catalyst. After catalytic treatment, perform solid-liquid separation. After the separated liquid is rotary evaporated to remove methanol and the solvent, intermediate I is obtained; Step 2: Add intermediate I and bromoethane to the second organic solvent, then add an acid-binding agent and the second catalyst, raise the temperature for reaction. After the reaction ends, rotary evaporate to dryness, and then after extraction, washing and drying, the second catalyst is separated out, and intermediate II is obtained; Step 3: Add to intermediate II in an alcohol solvent, add the second catalyst separated in Step 2, then dropwise add glacial acetic acid. After heating for reaction and purification, vitamin C ethyl ether is synthesized; In Step 1, the first catalyst is perfluorosulfonic acid resin, and the addition amount is 2%-6% of the mass of vitamin C; In Step 2, the second catalyst is sodium bromide, and the addition amount is 1.5%-5.5% of the mass of vitamin C.

2. The preparation method of vitamin C ethyl ether according to claim 1, characterized in that, In Step 1, the reaction temperature is 25-35°C, and the reaction time is 1-4 h.

3. The preparation method of vitamin C ethyl ether according to claim 1, characterized in that, In Step 1, the mass-volume ratio of vitamin C, 2,2-dimethoxypropane and the first solvent is (1.7-3.4) g:(1.5-3) g:(10-20) mL.

4. The preparation method of vitamin C ethyl ether according to claim 1, characterized in that, In Step 1, the first solvent is one or more of acetone, tetrahydrofuran, dichloromethane, acetonitrile; in Step 2, the second solvent is one or more of carbon tetrachloride, toluene, xylene, dimethyl sulfoxide, N,N-dimethylformamide.

5. The preparation method of vitamin C ethyl ether according to claim 1, characterized in that, In Step 2, the reaction temperature is 30-40°C, and the reaction time is 6-12 h.

6. The preparation method of vitamin C ethyl ether according to claim 1, characterized in that, In Step 2, the addition amount of bromoethane is 0.7-1.1 times the mass of vitamin C.

7. A method for preparing vitamin C ethyl ether according to claim 1, characterized in that, The acid-binding agent is triethylamine, and the addition amount is 0.6-0.9 times the mass of vitamin C.

8. The preparation method of vitamin C ethyl ether according to claim 1, characterized in that, In Step 3, the reaction temperature is 55-75°C, and the reaction time is 0.2-0.6 h.

9. The preparation method of vitamin C ethyl ether according to claim 1, characterized in that, In Step 3, the addition amount of the second catalyst separated in Step 2 is 1%-4% of the mass of vitamin C; the addition amount of glacial acetic acid is 1%-5% of the mass of vitamin C.

10. The preparation method of vitamin C ethyl ether according to claim 1, characterized in that, The alcohol solvent is methanol or ethanol, and the volume of the alcohol solvent is 5-15 mL.

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