Vitamin E acetate preparation method capable of reducing content of five-membered ring impurities

Abstract

The invention provides a preparation method of vitamin E acetate capable of reducing the content of five-membered ring impurities. The preparation method of the vitamin E acetate capable of reducing the content of the five-membered ring impurities comprises the following steps: in a solvent A, reacting [Et3NH] Cl with Lewis acid to obtain a triethylamine ionic liquid catalyst; in a solvent B, under the action of acid and a triethylamine ionic liquid catalyst, 2, 3, 5-trimethylhydroquinone and isophytol are subjected to a cyclization reaction to obtain vitamin E; vitamin E and acetic anhydride are esterified to obtain vitamin E acetate. The preparation method disclosed by the invention is simple, simple and convenient to operate, low in three-waste discharge amount, green, safe, environment-friendly, low in cost, high in product yield and purity, high in content, low in five-membered ring impurity content and suitable for industrial production, and process conditions are easy to realize; energy sources are saved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical synthesis of vitamins, and particularly relates to a method for preparing vitamin E acetate with reduced five-membered ring impurity content. Background Art

[0002] Vitamin E is a fat-soluble vitamin. Vitamin E acetate is one of the VE ester derivatives, which has the functions of anti-oxidation, moisturizing, enhancing the body's immunity, and eliminating free radicals in the body. Therefore, it has been widely used in food, medicine, feed and cosmetics.

[0003] The main method for producing vitamin E is to use 2,3,5-trimethylhydroquinone and isophytol as raw materials, and carry out cyclization, esterification, and distillation under the catalysis of zinc chloride and concentrated hydrochloric acid to obtain vitamin E acetate. The existing preparation method of vitamin E acetate has problems such as high product color number, high impurities, and low content; the content of five-membered ring impurities in the finished product of vitamin E acetate is generally around 1%; because the five-membered ring impurities and vitamin E acetate are isomers, they are difficult to separate, which directly restricts domestic vitamin production companies from producing high-content vitamins; in order to enter the international high-end medical-grade vitamin market in the future, it is necessary to analyze and control the impurities and study measures and means to reduce their content.

[0004] Existing technology:

[0005] Chinese patent CN109651255A discloses an imidazole ionic liquid and its preparation and application in the synthesis of vitamin E. The method requires first preparing an imidazole ionic liquid catalyst, reacting 2,3,5-trimethylhydroquinone diacetate with isophytol under the action of the catalyst, and then reacting with acetic anhydride to obtain vitamin E acetate. The patent does not mention the content of five-membered ring impurities in the product. At the same time, the amount of catalyst used is large, which is not an ideal industrial scale-up solution.

[0006] European patent EP1583753 (A1) provides a method for using Mn + (Rl SO 3- )n catalyst, catalyzing the reaction of 2,3,6-trimethylhydroquinone-1-acetate and isophytol to produce vitamin E acetate. However, the catalyst preparation process is relatively complicated and is not an ideal industrial scale-up scheme, and the content of five-membered ring impurities is not mentioned.

[0007] European patent EP603695 provides a method for preparing a supercritical CO 2In the system, vitamin E is synthesized by condensation reaction of trimethylhydroquinone and isophytol. The process is relatively complicated, the catalyst recovery and application are difficult, and there are problems such as serious equipment corrosion and troublesome waste liquid treatment. After the experiment was carried out according to this method, a large amount of isophytol deteriorated and generated heavy components.

[0008] Chinese patent CN 111646968 A provides a method for obtaining vitamin E by reacting 2,3,5-trimethylhydroquinone with isophytol in the presence of a catalyst and a co-catalyst. The catalyst is a heteropolyacid supported by a metal oxide and an organic phosphine compound. The catalyst used can be recycled and reused, but the catalyst preparation is complicated, and the five-membered ring impurity content is 0.46%, which is not an ideal industrial scale-up solution.

[0009] In summary, it can be seen that the current preparation method of vitamin E acetate has the problems of complex process, large amount of catalyst used, strict process requirements, severe equipment corrosion, high product color number, high content of five-membered ring impurities, low product content, etc.; In order to solve the above problems, the present invention is proposed. Summary of the invention

[0010] In view of the shortcomings of the prior art, the present invention provides a method for preparing vitamin E acetate with reduced five-membered ring impurity content. The preparation method of the present invention is simple, easy to operate, easy to achieve process conditions, energy saving, low three waste discharge, green, safe and environmentally friendly, low cost, high product yield and purity, high content, low five-membered ring impurity content, and suitable for industrial production.

[0011] In order to achieve the above invention object, the technical solution of the present invention is as follows:

[0012] A method for preparing vitamin E acetate with reduced five-membered ring impurity content, comprising the steps of:

[0013] (1) In solvent A, [Et 3 NH]Cl and Lewis acid react to obtain a triethylamine ionic liquid catalyst;

[0014] (2) In solvent B, under the action of acid and triethylamine ionic liquid catalyst, 2,3,5-trimethylhydroquinone and isophytol undergo a cyclization reaction to obtain vitamin E;

[0015] (3) Vitamin E and acetic anhydride are esterified to obtain vitamin E acetate.

[0016] Preferably according to the present invention, in step (1), solvent A is n-heptane or petroleum ether.

[0017] Preferably according to the present invention, in step (1), the Lewis acid is zinc chloride or zinc bromide.

[0018] According to the preferred embodiment of the present invention, in step (1), [Et 3 The molar ratio of NH]Cl to Lewis acid is 1:2-3.

[0019] According to the preferred embodiment of the present invention, in step (1), [Et 3 The mass ratio of NH]Cl to solvent A is 1:3-5.

[0020] According to the preferred embodiment of the present invention, in step (1), the reaction temperature is 80-100°C, the reaction time is 8-12h, and the reaction is carried out under the protection of an inert gas, reflux, and stirring. Preferably, the inert gas is nitrogen or argon.

[0021] Preferably, in step (1), the post-treatment method of the reaction solution obtained by the reaction is as follows: the reaction solution is washed, the solvent is removed by rotary evaporation, and the reaction solution is dried to obtain a triethylamine ionic liquid catalyst.

[0022] Preferably, in step (2), solvent B is one or a combination of two or more of ethyl acetate, diethyl carbonate, dimethyl carbonate, methanol or ethanol; and the mass ratio of 2,3,5-trimethylhydroquinone to solvent B is 1:2-5.

[0023] Preferably, according to the present invention, in step (2), the acid is a hydrochloric acid aqueous solution with a mass concentration of 30-32%; the mass of the acid is 4-5% of the mass of 2,3,5-trimethylhydroquinone.

[0024] Preferably according to the present invention, in step (2), the mass of the triethylamine ionic liquid catalyst is 10-40% of the mass of 2,3,5-trimethylhydroquinone.

[0025] Preferably according to the present invention, in step (2), the molar ratio of 2,3,5-trimethylhydroquinone to isophytol is 1:1 to 1:1.1.

[0026] According to the preferred embodiment of the present invention, in step (2), isophytol is added dropwise to the reaction system at 20-60° C. with stirring and under the protection of an inert gas, wherein the inert gas is nitrogen or argon.

[0027] According to the preferred embodiment of the present invention, in step (2), the cyclization reaction temperature is 20-60°C, the reaction time is 1-10 hours, and the reaction is carried out under inert gas protection and stirring. Preferably, the cyclization reaction temperature is 30-40°C, the reaction time is 2-5 hours, and the inert gas is nitrogen or argon.

[0028] Preferably, in step (2), the post-treatment method of the reaction liquid obtained by the cyclization reaction comprises the steps of: distilling the reaction liquid to recover the solvent, the residue being vitamin E and triethylamine ionic liquid catalyst; adding petroleum ether or n-heptane to dissolve the vitamin E, and then adding methanol for extraction, the upper layer being an organic solvent layer containing vitamin E, and the lower layer being a triethylamine ionic liquid catalyst-methanol layer; removing methanol from the lower layer by distillation to recover the triethylamine ionic liquid catalyst, which can be reused as a catalyst; and directly carrying out the next step reaction on the upper layer.

[0029] Preferably according to the present invention, the molar ratio of acetic anhydride in step (3) to 2,3,5-trimethylhydroquinone in step (2) is (1.1-1.5):1.

[0030] According to the preferred embodiment of the present invention, in step (3), the esterification reaction temperature is 10-50°C, the reaction time is 1-3 hours, and the reaction is carried out under stirring conditions. Preferably, the esterification reaction temperature is 20-40°C.

[0031] Preferably, in step (3) of the present invention, the post-treatment method of the reaction solution obtained by the reaction comprises the steps of: adding water and activated carbon to the reaction solution, controlling the temperature at 30-40°C, stirring for 20-40 minutes, and filtering; separating the liquids, washing the organic phase with water until the pH of the washing liquid reaches 7.0, and separating the liquids to obtain the organic phase; and distilling the organic phase to obtain vitamin E acetate.

[0032] The method of the present invention is described as the following synthetic route 1:

[0033]

[0034] The main reaction of 2,3,5-trimethylhydroquinone and isophytol in the present invention is a Friedel-Crafts reaction with double bonds. The double bonds in isophytol are more active than halogens, and the carbon cation formed by combining with hydrogen ions is more stable at the α end, but due to steric hindrance, the main reaction product is the Friedel-Crafts alkylation reaction product at the β end, and a small amount of α end reaction product five-membered ring impurity (synthetic route 2) is generated at the same time. The generated α end reaction product five-membered ring impurity and vitamin E are isomers and are difficult to separate, so that the five-membered ring impurity is further subjected to the next step of esterification reaction to obtain a five-membered ring impurity (I), which is also an isomer with vitamin E acetate and is difficult to separate.

[0035]

[0036] The use of the triethylamine ionic liquid catalyst of the present invention makes it easier for the reaction of 2,3,5-trimethylhydroquinone and isophytol to generate a β-terminal Friedel-Crafts alkylation product, i.e., the main product vitamin E of the present invention, and reduces the generation of five-membered ring impurities, thereby improving the purity and content of the target product vitamin E acetate and reducing the content of the five-membered ring impurities.

[0037] Technical features and beneficial effects of the present invention:

[0038] 1. The preparation method of vitamin E acetate of the present invention is simple, easy to operate, easy to achieve process conditions, energy saving, less separation process, less wastewater, green, safe and environmentally friendly, high reaction atomic economy, low cost, and suitable for industrial production.

[0039] 2. The present invention utilizes the catalytic activation effect of triethylamine ionic liquid to activate the β-C reaction site of isophytol, prepares vitamin E with high selectivity, and reduces the content of five-membered ring impurities. The method of the present invention has high reaction selectivity, high yield and purity of the target product, and effectively reduces the content of five-membered ring impurities in the product.

[0040] 3. In the process of synthesizing vitamin E, ionic liquid as a catalyst just solves the problems of poor catalyst selectivity, poor catalytic activity, and inability to be recycled. The preparation method of the ionic liquid catalyst of the present invention is simple, low-cost, green, safe and environmentally friendly, with a small amount of catalyst, good catalytic selectivity and activity, and can be recycled and reused, and has broad application prospects in the synthetic vitamin E industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 HPLC spectrum of the product prepared in Example 3;

[0042] Figure 2 HPLC spectrum of the product prepared in Example 4;

[0043] Figure 3 The HPLC spectrum of the product prepared in comparative example. DETAILED DESCRIPTION

[0044] The present invention is described in detail below with reference to the embodiments, but the present invention is not limited thereto.

[0045] The raw materials and reagents used in the examples are all commercially available products. The yields in the examples are molar yields, unless otherwise specified.

[0046] Example 1: Preparation of ionic liquid

[0047] [Et 3 NH]Cl (68.83 g, 0.5 mol) and ZnCl 2 (149.94 g, 1.1 mol) was dissolved in 275 g of n-heptane, and reacted under reflux stirring at 90°C for 10 h in a nitrogen atmosphere to obtain a reaction solution, which was washed with water. The organic phase was evaporated to remove n-heptane under reduced pressure and dried in vacuo to obtain a triethylamine ionic liquid catalyst with a yield of 87%.

[0048] Example 2: Preparation of ionic liquid

[0049] [Et 3 NH]Cl (68.83 g, 0.5 mol) and ZnCl 2 (136.32 g, 1 mol) was dissolved in 275 g of n-heptane, and reacted under reflux stirring at 90°C for 10 h in a nitrogen atmosphere to obtain a reaction solution, which was washed with water. The organic phase was evaporated under reduced pressure to remove n-heptane and dried in vacuo to obtain a triethylamine ionic liquid catalyst with a yield of 85%.

[0050] Example 3: Preparation of Vitamin E Acetate

[0051] In a 500mL four-necked flask, first add 15g of the triethylamine ionic liquid catalyst prepared by the method of Example 1 and 200mL of ethyl acetate, weigh 50.0g of 2,3,5-trimethylhydroquinone and add it to the four-necked flask, and then add 2.4g of concentrated hydrochloric acid with a mass concentration of 32%. After 2,3,5-trimethylhydroquinone is completely dissolved, 104.75g of isophytol (IP) is slowly added dropwise with a constant pressure dropping funnel at 40°C under stirring. After the dropwise addition, stir and react for 3h at 40°C, and nitrogen protection is used during the dropwise addition and reaction. After the reaction is completed, ethyl acetate is distilled and recovered, and the residue is vitamin E and ionic liquid. 200mL of petroleum ether is added to dissolve vitamin E. The mixed solution is placed in a separating funnel, and 80mL of methanol is added to extract and separate the ionic liquid. The upper layer is a petroleum ether layer (dissolved with vitamin E), and the lower layer is an ionic liquid layer. The ionic liquid layer is separated. The ionic liquid layer can be recycled and reused as a catalyst for the condensation reaction after distillation to remove the methanol therein.

[0052] Add 45.5g of acetic anhydride to the petroleum ether layer, control the temperature at 40℃ and stir for 3h. After the reaction is completed, add 50g of water and 2.25g of activated carbon to the reaction solution, control the temperature at 30-40℃, stir for 30min, and filter; separate the liquids, wash the organic phase with 100g of water twice until the pH of the eluate is 7.0, separate the liquids to obtain the organic phase; recover the petroleum ether by distillation to obtain vitamin E acetate. The yield of vitamin E acetate is 95%, the content of five-membered ring impurities is 0.27%, and the purity is 99.01%. HPLC spectrum is as follows Figure 1 shown.

[0053] Example 4: Preparation of Vitamin E Acetate

[0054] In a 500mL four-necked flask, first add 10.0g of the triethylamine ionic liquid catalyst prepared by the method of Example 1 and 200mL of ethyl acetate, weigh 50.0g of 2,3,5-trimethylhydroquinone and add it to the four-necked flask, and then add 2.4g of concentrated hydrochloric acid with a mass concentration of 32%. After 2,3,5-trimethylhydroquinone is completely dissolved, 104.75g of isophytol (IP) is slowly added dropwise with a constant pressure dropping funnel at 40°C under stirring. After the dropwise addition, stir and react for 3h at 40°C, and nitrogen protection is used during the dropwise addition and reaction. After the reaction is completed, ethyl acetate is distilled and recovered, and the residue is vitamin E and ionic liquid. 200mL of petroleum ether is added to dissolve vitamin E. The mixed solution is placed in a separating funnel, and 80mL of methanol is added to extract and separate the ionic liquid. The upper layer is a petroleum ether layer (dissolved with vitamin E), and the lower layer is an ionic liquid layer. The ionic liquid layer is separated. The ionic liquid layer can be recycled and reused as a catalyst for the condensation reaction after distillation to remove the methanol therein.

[0055] Add 45.5g of acetic anhydride to the petroleum ether layer, control the temperature at 40℃ and stir for 3h. After the reaction is completed, add 50g of water and 2.25g of activated carbon to the reaction solution, control the temperature at 30-40℃, stir for 30min, and filter; separate the liquids, wash the organic phase with 100g of water twice until the pH of the eluate is 7.0, separate the liquids to obtain the organic phase; distill and recover the petroleum ether to obtain vitamin E acetate. The yield of vitamin E acetate is 94%, and the content of five-membered ring impurities is 0.54%. The purity is 99.07%. HPLC spectrum is as follows Figure 2 shown.

[0056] Example 5: Preparation of Vitamin E Acetate

[0057] In a 500mL four-necked flask, first add 20.0g of the triethylamine ionic liquid catalyst prepared by the method of Example 1 and 200mL of ethyl acetate, weigh 50.0g of 2,3,5-trimethylhydroquinone and add it to the four-necked flask, and then add 2.4g of concentrated hydrochloric acid with a mass concentration of 32%. After 2,3,5-trimethylhydroquinone is completely dissolved, 104.75g of isophytol (IP) is slowly added dropwise with a constant pressure dropping funnel at 40°C under stirring. After the dropwise addition, stir and react for 3h at 40°C, and nitrogen protection is used during the dropwise addition and reaction. After the reaction is completed, ethyl acetate is distilled and recovered, and the residue is vitamin E and ionic liquid. 200mL of petroleum ether is added to dissolve vitamin E. The mixed solution is placed in a separatory funnel, and 80mL of methanol is added to extract and separate the ionic liquid. The upper layer is a petroleum ether layer (dissolved with vitamin E), and the lower layer is an ionic liquid layer. The ionic liquid layer is separated. The ionic liquid layer can be recycled and reused as a catalyst for the condensation reaction after distillation to remove the methanol therein.

[0058] Add 45.5g of acetic anhydride to the petroleum ether layer, control the temperature at 40℃ and stir for 3h. After the reaction is completed, add 50g of water and 2.25g of activated carbon to the reaction solution, control the temperature at 30-40℃, stir for 30min, and filter by suction; separate the liquids, wash the organic phase with 100g of water twice until the pH of the eluate is 7.0, separate the liquids to obtain the organic phase; distill and recover the petroleum ether to obtain vitamin E acetate. The yield of vitamin E acetate is 95.5%, and the content of five-membered ring impurities is 0.19%. The purity is 99.27%.

[0059] Example 6: Preparation of Vitamin E Acetate

[0060] In a 500mL four-necked flask, first add 15.0g of the triethylamine ionic liquid catalyst prepared by the method of Example 1 and 200mL of diethyl carbonate, weigh 50.0g of 2,3,5-trimethylhydroquinone and add it to the four-necked flask, and then add 2.4g of concentrated hydrochloric acid with a mass concentration of 32%. After 2,3,5-trimethylhydroquinone is completely dissolved, 104.75g of isophytol (IP) is slowly added dropwise with a constant pressure dropping funnel at 40°C under stirring. After the dropwise addition, stir and react for 3h at 40°C, and nitrogen protection is used during the dropwise addition and reaction. After the reaction is completed, diethyl carbonate is distilled and recovered, and the residue is vitamin E and ionic liquid. 200mL of petroleum ether is added to dissolve vitamin E. The mixed solution is placed in a separatory funnel, and 80mL of methanol is added to extract and separate the ionic liquid. The upper layer is a petroleum ether layer (dissolved with vitamin E), and the lower layer is an ionic liquid layer. The ionic liquid layer is separated. The ionic liquid layer can be recovered and reused as a catalyst for the condensation reaction after methanol is removed by distillation.

[0061] Add 45.5g of acetic anhydride to the petroleum ether layer, control the temperature at 40℃ and stir for 3h. After the reaction is completed, add 50g of water and 2.25g of activated carbon to the reaction solution, control the temperature at 30-40℃, stir for 30min, and filter by suction; separate the liquids, wash the organic phase with 100g of water twice until the pH of the eluate is 7.0, separate the liquids to obtain the organic phase; distill and recover the petroleum ether to obtain vitamin E acetate. The yield of vitamin E acetate is 94%, and the content of five-membered ring impurities is 0.99%. The purity is 98.16%.

[0062] Comparative Example: Preparation of Vitamin E Acetate

[0063] In a 500mL four-necked flask, first add 2.69g zinc chloride and 200mL ethyl acetate, weigh 50.0g 2,3,5-trimethylhydroquinone and add it to the four-necked flask, and then add 2.4g concentrated hydrochloric acid with a mass concentration of 32%. After 2,3,5-trimethylhydroquinone is completely dissolved, 104.75g isophytol (IP) is slowly added dropwise with a constant pressure dropping funnel under stirring at 40°C. After the dropwise addition, stir and react for 3h at 40°C, and nitrogen protection is used during the dropwise addition and reaction. After the reaction is completed, ethyl acetate is distilled and recovered, and 200mL petroleum ether is added to dissolve vitamin E. The mixed solution is placed in a separatory funnel, and 100mL water is added to extract and separate zinc chloride. The upper layer is the petroleum ether layer (dissolved with vitamin E), and the lower layer is the catalyst layer.

[0064] Add 45.5g of acetic anhydride to the petroleum ether layer, control the temperature at 40℃ and stir for 3h. After the reaction is completed, add 50g of water and 2.25g of activated carbon to the reaction solution, control the temperature at 30-40℃, stir for 30min, and filter; separate the liquids, wash the organic phase with 100g of water twice until the pH of the eluate is 7.0, separate the liquids to obtain the organic phase; recover the petroleum ether by distillation to obtain vitamin E acetate. The yield of vitamin E acetate is 94%, the content of five-membered ring impurities is 1.12%, and the purity is 97.90%. HPLC spectrum is as follows Figure 3 shown.

Claims

1. A method for preparing vitamin E acetate with reduced five-membered ring impurity content, comprising the steps of: (1) In solvent A, [Et3NH]Cl and Lewis acid are reacted to obtain a triethylamine ionic liquid catalyst; (2) In solvent B, under the action of acid and triethylamine ionic liquid catalyst, 2,3,5-trimethylhydroquinone and isophytol undergo a cyclization reaction to obtain vitamin E; (3) Vitamin E and acetic anhydride are esterified to obtain vitamin E acetate.

2. The method for preparing vitamin E acetate with reduced five-membered ring impurity content according to claim 1, characterized in that: In step (1), solvent A is n-heptane or petroleum ether.

3. The method for preparing vitamin E acetate with reduced five-membered ring impurity content according to claim 1, characterized in that: In step (1), the Lewis acid is zinc chloride or zinc bromide.

4. The method for preparing vitamin E acetate with reduced five-membered ring impurity content according to claim 1, characterized in that: In step (1), one or more of the following conditions are included: i. The molar ratio of [Et3NH]Cl to Lewis acid is 1:2-3; ii. The mass ratio of [Et3NH]Cl to solvent A is 1:3-5.

5. The method for preparing vitamin E acetate with reduced five-membered ring impurity content according to claim 1, characterized in that: In step (1), the reaction temperature is 80-100° C., the reaction time is 8-12 h, and the reaction is carried out under inert gas protection, reflux, and stirring conditions; preferably, the inert gas is nitrogen or argon.

6. The method for preparing vitamin E acetate with reduced five-membered ring impurity content according to claim 1, characterized in that: In step (2), one or more of the following conditions are included: i. Solvent B is one or a combination of two or more of ethyl acetate, diethyl carbonate, dimethyl carbonate, methanol or ethanol; the mass ratio of 2,3,5-trimethylhydroquinone to solvent B is 1:2-5; ii. The acid is a hydrochloric acid aqueous solution with a mass concentration of 30-32%; the mass of the acid is 4-5% of the mass of 2,3,5-trimethylhydroquinone; iii. The molar ratio of 2,3,5-trimethylhydroquinone to isophytol is 1:1 to 1:1.1; iv. Isophytol is added dropwise into the reaction system at 20-60° C. with stirring and under the protection of an inert gas; the inert gas is nitrogen or argon.

7. The method for preparing vitamin E acetate with reduced five-membered ring impurity content according to claim 1, characterized in that: In step (2), the mass of the triethylamine ionic liquid catalyst is 10-40% of the mass of 2,3,5-trimethylhydroquinone.

8. The method for preparing vitamin E acetate with reduced five-membered ring impurity content according to claim 1, characterized in that: In step (2), the cyclization reaction temperature is 20-60°C, the reaction time is 1-10 hours, and the reaction is carried out under inert gas protection and stirring conditions; preferably, the cyclization reaction temperature is 30-40°C, the reaction time is 2-5 hours, and the inert gas is nitrogen or argon.

9. The method for preparing vitamin E acetate with reduced five-membered ring impurity content according to claim 1, characterized in that: In step (2), the post-treatment method of the reaction liquid obtained by the cyclization reaction comprises the steps of: distilling the reaction liquid to recover the solvent, the residue is vitamin E and triethylamine ionic liquid catalyst; adding petroleum ether or n-heptane to dissolve the vitamin E, and then adding methanol for extraction, the upper layer is an organic solvent layer containing vitamin E, and the lower layer is a triethylamine ionic liquid catalyst-methanol layer; distilling the lower layer to remove methanol and recover the triethylamine ionic liquid catalyst, which can be reused as a catalyst; and directly carrying out the next step reaction on the upper layer.

10. The method for preparing vitamin E acetate with reduced five-membered ring impurity content according to claim 1, characterized in that: In step (3), one or more of the following conditions are included: i. The molar ratio of acetic anhydride in step (3) to 2,3,5-trimethylhydroquinone in step (2) is (1.1-1.5):1; ii. The temperature of the esterification reaction is 10-50°C, the reaction time is 1-3 hours, and the reaction is carried out under stirring conditions; preferably, the esterification reaction temperature is 20-40°C; iii. The post-treatment method of the reaction liquid obtained by the reaction comprises the steps of: adding water and activated carbon to the reaction liquid, controlling the temperature at 30-40°C, stirring for 20-40 minutes, filtering; separating the liquids, washing the organic phase with water until the pH of the washing liquid is 7.0, separating the liquids to obtain the organic phase; and distilling the organic phase to obtain vitamin E acetate.

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