A preparation process of vitamin E acetate

Abstract

The present invention belongs to the technical field of chemical synthesis, and discloses a preparation process of vitamin E acetate. Using a modified resin as a catalyst, 2,3,5-trimethylhydroquinone diester as a solute, and acetic acid as a solvent, an acetic acid solution of 2,3,5-trimethylhydroquinone diester and phytol are simultaneously pumped into a microchannel reactor for transesterification reaction to obtain vitamin E acetate; the catalyst is a resin loaded with a proton strong acid and a Lewis acid, and the catalyst is loaded in the microchannel reactor. The present invention utilizes the microchannel reactor to be conducive to improving the mass transfer effect of the reaction, and the loaded modified macromolecular catalyst is conducive to increasing the contact area between the reaction liquid and the catalyst, thereby increasing the reaction rate, reducing the reaction time, and improving the reaction yield; at the same time, using the modified resin catalyst of the present invention can reduce the post-treatment process, and the recovered acetic acid can be directly refluxed to the initial stage of the reaction, reducing the generation of three wastes.

Description

Technical Field

[0001] The present invention relates to the technical field of pharmaceutical synthesis, and particularly to a preparation process of vitamin E acetate. Background Art

[0002] Vitamin E acetate, also known as vitamin E acetate and tocopheryl acetate, is readily soluble in organic solvents such as alcohols and ethers and in oils and fats, is almost insoluble in water, is easily oxidized when exposed to air, has a wide range of pharmacological effects in the medical field, can also be used as an antioxidant for oils and fats, and has a moisturizing effect on the skin in cosmetics.

[0003] The existing synthesis methods of vitamin E acetate generally are: adding 2,3,5-trimethylhydroquinone, a solvent and a catalyst system into a reaction kettle, stirring until dissolved, then dropwise adding phytol under the protection of nitrogen, ending the reaction after heating and holding the temperature, separating the liquid, recovering the solvent by reduced pressure distillation, and then generating crude vitamin E acetate after washing and extracting the reaction solution. However, the existing general process route for synthesizing vitamin E acetate has the following deficiencies: the catalytic system is an acidic system, is readily soluble in water, and will cause loss of the catalyst during the recovery process, increasing the difficulty of treating the three wastes; since the catalyst is a strongly corrosive protonic strong acid and Lewis acid, the equipment material requirements are relatively high during the treatment process and the post-treatment process is cumbersome; the properties of phytol are relatively active, and the dropwise addition method can reduce the loss of phytol, but at the same time will prolong the reaction time, resulting in a relatively high vitamin E content, and secondary esterification is required for subsequent preparation of vitamin E acetate, increasing the cost.

[0004] Therefore, how to provide a preparation process of vitamin E acetate that is green and environmentally friendly, has a simple process, high efficiency, and low cost is a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0005] In view of this, the present invention provides a preparation process of vitamin E acetate, using a macroporous resin modified by a protonic strong acid and a Lewis acid as a catalyst, loading it onto a microchannel reactor to increase the contact area between the reaction solution and the catalyst, accelerating the reaction rate, shortening the reaction time, reducing the vitamin E content, reducing the catalyst loss and post-treatment steps, and improving the reaction yield.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] A preparation process of vitamin E acetate, using a modified resin as a catalyst, 2,3,5-trimethylhydroquinone and phytol as solutes, and acetic acid as a solvent to carry out an ester exchange reaction in a microchannel reactor to obtain vitamin E acetate;

[0008] The catalyst is a resin loaded with a proton strong acid and a Lewis acid, and the catalyst is loaded in the microchannel reactor.

[0009] Preferably, in the above preparation process of vitamin E acetate, the preparation method of the modified resin comprises the following steps:

[0010] (1) Take a mixed solution of a proton strong acid and a Lewis acid dissolved in an organic solution, soak the macroporous resin in the mixed solution until the macroporous resin is completely adsorbed; specifically, judge whether the adsorption is complete by detecting the residues of the proton strong acid and the Lewis acid in the mixed solution;

[0011] (2) Carry out vacuum carbonization treatment on the completely adsorbed macroporous resin to obtain the modified resin.

[0012] Preferably, in the above preparation process of vitamin E acetate, the organic solution is a mixed solution of an organic solvent and water, and the organic solvent includes any one or more of acetone, methanol, and ethanol.

[0013] Preferably, in the above preparation process of vitamin E acetate, the proton strong acid includes hydrobromic acid and hydrochloric acid, and the Lewis acid includes zinc chloride and zinc bromide.

[0014] Preferably, in the above preparation process of vitamin E acetate, the temperature of the vacuum carbonization in step (2) is 40 - 60 °C, and the vacuum degree is 60 - 100 KPa.

[0015] Preferably, in the above preparation process of vitamin E acetate, the volume ratio of the mixed solution of the proton strong acid and the Lewis acid to the organic solution is 0.5 - 0.8:1; more preferably, the molar ratio of the proton strong acid to the Lewis acid is 1:1 - 1.5.

[0016] Preferably, in the above preparation process of vitamin E acetate, the transesterification reaction time is 1 - 15 min, and the temperature is 35 - 50 °C.

[0017] Preferably, in the above preparation process of vitamin E acetate, the mass ratio of 2,3,5 - trimethylhydroquinone diacetate to acetic acid is 1:0.2 - 0.5, and the mass ratio of 2,3,5 - trimethylhydroquinone diacetate to isophytol is 1:1 - 1.2.

[0018] Preferably, in the above preparation process of vitamin E acetate, it further comprises: separating the vitamin E acetate from acetic acid and then carrying out rectification to obtain the finished product of vitamin E acetate.

[0019] Preferably, in the above preparation process of vitamin E acetate, the vitamin E acetate and acetic acid are separated by vacuum distillation, and the separation temperature is 60 - 80 °C.

[0020] Preferably, in the preparation process of the above-mentioned vitamin E acetate, the vitamin E acetate is purified by vacuum rectification, and the rectification and purification temperature is 200 - 230 °C.

[0021] The present invention provides a preparation process of vitamin E acetate. Compared with the prior art, its beneficial effects are as follows: The present invention utilizes a microchannel reactor to facilitate improving the mass transfer effect of the reaction. The loaded modified macromolecular catalyst is beneficial to increasing the contact area between the reaction solution and the catalyst, thereby increasing the reaction rate, reducing the reaction time, and improving the reaction yield; at the same time, using the modified resin catalyst of the present invention can reduce the post-treatment process, and the recovered acetic acid can be directly refluxed to the initial stage of the reaction, reducing the generation of three wastes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0023] Figure 1 It is a schematic diagram of the catalytic reaction mechanism of vitamin E acetate of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0025] Example 1

[0026] (1) Take a mixed solution of hydrobromic acid and zinc bromide dissolved in an organic solution with a molar ratio of 1:1, where the volume ratio of the hydrobromic acid and zinc bromide solution to the organic solution is 0.5:1. Immerse the polystyrene macroporous resin in the mixed solution until the macroporous resin is completely adsorbed.

[0027] (2) Carry out vacuum carbonization treatment on the completely adsorbed macroporous resin under the conditions of 60 KPa and 60 °C to obtain modified resin A, and load the modified resin A on the microchannel reactor.

[0028] Example 2

[0029] (1) Take a mixed solution of hydrochloric acid and zinc chloride with a molar ratio of 1:1.2 dissolved in an organic solution, where the volume ratio of hydrochloric acid, zinc chloride solution to the organic solution is 0.6:1. Immerse the macroporous resin in the mixed solution until the macroporous resin is completely adsorbed;

[0030] (2) Carry out vacuum carbonization treatment on the completely adsorbed macroporous resin under the conditions of 75 KPa and 55 °C to obtain modified resin B, and load the modified resin B onto the microchannel reactor.

[0031] Example 3

[0032] (1) Take a mixed solution of hydrochloric acid and zinc chloride with a molar ratio of 1:1.5 dissolved in an organic solution, where the volume ratio of hydrochloric acid, zinc chloride solution to the organic solution is 0.7:1. Immerse the macroporous resin in the mixed solution until the macroporous resin is completely adsorbed;

[0033] (2) Carry out vacuum carbonization treatment on the completely adsorbed macroporous resin under the conditions of 85 KPa and 45 °C to obtain modified resin C, and load the modified resin C onto the microchannel reactor.

[0034] Example 4

[0035] (1) Take a mixed solution of hydrochloric acid and zinc chloride with a molar ratio of 1:1.3 dissolved in an organic solution, where the volume ratio of hydrochloric acid, zinc chloride solution to the organic solution is 0.8:1. Immerse the macroporous resin in the mixed solution until the macroporous resin is completely adsorbed;

[0036] (2) Carry out vacuum carbonization treatment on the completely adsorbed macroporous resin under the conditions of 100 KPa and 40 °C to obtain modified resin D, and load the modified resin D onto the microchannel reactor.

[0037] Example 5

[0038] (1) Take a mixed solution of hydrochloric acid and zinc chloride with a molar ratio of 1:1.1 dissolved in an organic solution, where the volume ratio of hydrochloric acid, zinc chloride solution to the organic solution is 0.4:1. Immerse the macroporous resin in the mixed solution until the macroporous resin is completely adsorbed;

[0039] (2) Carry out vacuum carbonization treatment on the completely adsorbed macroporous resin under the conditions of 80 KPa and 40 °C to obtain modified resin E, and load the modified resin E onto the microchannel reactor.

[0040] Example 6

[0041] (1) Take a mixed solution of hydrochloric acid and zinc chloride with a molar ratio of 1:1.4 dissolved in an organic solution, where the volume ratio of hydrochloric acid, zinc chloride solution to the organic solution is 0.9:1. Immerse the macroporous resin in the mixed solution until the macroporous resin is completely adsorbed;

[0042] (2) The macroporous resin with complete adsorption is subjected to vacuum carbonization treatment under the conditions of 100 KPa and 40 °C to obtain modified resin F, and the modified resin F is loaded onto a microchannel reactor.

[0043] Example 7

[0044] (1) Take a mixed solution of sulfuric acid and zinc sulfate with a molar ratio of 1:1 dissolved in an organic solution, where the volume ratio of sulfuric acid and zinc sulfate solution to the organic solution is 0.8:1. Immerse the macroporous resin in the mixed solution until the macroporous resin is completely adsorbed;

[0045] (2) The macroporous resin with complete adsorption is subjected to vacuum carbonization treatment under the conditions of 120 KPa and 40 °C to obtain modified resin G, and the modified resin G is loaded onto a microchannel reactor.

[0046] Comparative Example 1

[0047] (1) Take a mixed solution of hydrobromic acid in an organic solution, where the volume ratio of hydrobromic acid to the organic solution is 0.5:1. Immerse the polystyrene macroporous resin in the mixed solution until the macroporous resin is completely adsorbed;

[0048] (2) The macroporous resin with complete adsorption is subjected to vacuum carbonization treatment under the conditions of 60 KPa and 60 °C to obtain modified resin A, and the modified resin A1 is loaded onto a microchannel reactor.

[0049] Comparative Example 2

[0050] (1) Take a mixed solution of zinc bromide dissolved in an organic solution, where the volume ratio of zinc bromide solution to the organic solution is 0.5:1. Immerse the polystyrene macroporous resin in the mixed solution until the macroporous resin is completely adsorbed;

[0051] (2) The macroporous resin with complete adsorption is subjected to vacuum carbonization treatment under the conditions of 60 KPa and 60 °C to obtain modified resin A, and the modified resin A2 is loaded onto a microchannel reactor.

[0052] Example 8

[0053] (1) Dissolve 500 g of 2,3,5-trimethylhydroquinone diacetate in 100 g of acetic acid to form an acetic acid solution. Pump the acetic acid solution into the microchannel reactor loaded with modified resin A at a rate of 18.48 g / min and isophytol into the microchannel reactor at a rate of 30 g / min. The microchannel reactor is heated to 35 °C by a thermostatic bath, and the residence time is maintained for 15 min. After the equipment feeds continuously and stably, 38.48 g of product is taken out per minute. The VE condensation conversion rate is measured by the internal standard method to be 99.8%, and the yield is 99.1%;

[0054] (2) Take the product from the outlet of the microchannel reactor and separate acetic acid by vacuum distillation at 60 °C. The acetic acid content in the finished product of vitamin E acetate in the bottom of the distillation column at the separation end is about 0.2%. Take the crude vitamin E acetate to the rectification column and carry out vacuum rectification at 200 °C to obtain the finished vitamin E acetate with a purity of 99.5%, and the content of the finished product in the bottom of the column is 0.1%.

[0055] Example 9

[0056] (1) Dissolve 500 g of 2,3,5-trimethylhydroquinone diacetate in 100 g of acetic acid to form an acetic acid solution. Pump the acetic acid solution into the microchannel reactor loaded with modified resin B at a rate of 20.07 g / min and isophytol into the microchannel reactor at a rate of 32.58 g / min respectively by a peristaltic pump. The microchannel reactor is heated to 40 °C by a thermostatic bath circulator, and the residence time is maintained at 13.8 min. After the feed of the equipment is continuous and stable, 52.65 g of product is taken out per minute. By measuring the sample by the internal standard method, it can be obtained that the condensation conversion rate of VE is 99.6% and the yield is 99.3%;

[0057] (2) Take the product from the outlet of the microchannel reactor and separate acetic acid by vacuum distillation at 70 °C. The acetic acid content in the finished product of vitamin E acetate in the bottom of the distillation column at the separation end is about 0.2%. Take the crude vitamin E acetate to the rectification column and carry out vacuum rectification at 210 °C to obtain the finished vitamin E acetate with a purity of 99.5%, and the content of the finished product in the bottom of the column is 0.1%.

[0058] Example 10

[0059] (1) Dissolve 5000 g of 2,3,5-trimethylhydroquinone diacetate in 1000 g of acetic acid to form an acetic acid solution. Pump the acetic acid solution into the microchannel reactor loaded with modified resin C at a rate of 30 g / min and isophytol into the microchannel reactor at a rate of 40.59 g / min respectively by a peristaltic pump. The microchannel reactor is heated to 50 °C by a thermostatic bath circulator, and the residence time is maintained at 10.3 min. After the feed of the equipment is continuous and stable, 52.65 g of product is taken out per minute. By measuring the sample by the internal standard method, it can be obtained that the condensation conversion rate of VE is 99.6% and the yield is 99.3%;

[0060] (2) Take the product from the outlet of the microchannel reactor and separate acetic acid by vacuum distillation at 80 °C. The acetic acid content in the finished product of vitamin E acetate in the bottom of the distillation column at the separation end is about 0.2%. Take the crude vitamin E acetate from the column to the rectification column and carry out vacuum rectification at 220 °C to obtain the finished vitamin E acetate with a purity of 99.5%, and the content of the finished product in the bottom of the column is 0.1%.

[0061] Example 11

[0062] (1) Dissolve 5000 g of trimethylhydroquinone diester in 1000 g of acetic acid to form an acetic acid solution. Pump the acetic acid solution into the microchannel reactor loaded with modified resin D at a rate of 60 g / min and isophytol into the microchannel reactor at a rate of 97.41 g / min using a peristaltic pump. The microchannel reactor is heated to 45 °C by a thermostatic bath circulator, and the residence time is maintained at 4.6 min. After the feed of the equipment is continuous and stable, 157.41 g of product is withdrawn per minute. By measuring the sample using the internal standard method, the condensation conversion rate of VE is 99.2%, and the yield is 99.2%;

[0063] (2) Take the product at the outlet of the microchannel reaction and separate acetic acid by vacuum distillation at 65 °C. The acetic acid content in the finished product of vitamin E acetate at the bottom of the separation end point is about 0.2%; Take the crude product of vitamin E acetate to the distillation column and perform vacuum distillation at 230 °C to obtain the finished product of vitamin E acetate with a purity of 99.5%, and the content of the finished product at the bottom of the column is 0.1%.

[0064] Example 12

[0065] (1) Dissolve 500 g of 2,3,5-trimethylhydroquinone diester in 100 g of acetic acid to form an acetic acid solution. Pump the acetic acid solution into the microchannel reactor loaded with modified resin A at a rate of 18.48 g / min and isophytol into the microchannel reactor at a rate of 30 g / min using a peristaltic pump. The microchannel reactor is heated to 35 °C by a thermostatic bath circulator, and the residence time is maintained at 20 min. After the feed of the equipment is continuous and stable, 38.48 g of product is withdrawn per minute. By measuring the sample using the internal standard method, the condensation conversion rate of VE is 99.7%, and the yield is 99.1%;

[0066] (2) Take the product at the outlet of the microchannel reaction and separate acetic acid by vacuum distillation at 60 °C. The acetic acid content in the finished product of vitamin E acetate at the bottom of the separation end point is about 0.2%; Take the crude product of vitamin E acetate to the distillation column and perform vacuum distillation at 180 °C to obtain the finished product of vitamin E acetate with a purity of 99.0%, and the content of the finished product at the bottom of the column is 0.05%.

[0067] Example 13

[0068] (1) Dissolve 500 g of 2,3,5-trimethylhydroquinone diester in 100 g of acetic acid to form an acetic acid solution. Pump the acetic acid solution into the microchannel reactor loaded with modified resin E at a rate of 18.48 g / min and isophytol into the microchannel reactor at a rate of 30 g / min using a peristaltic pump. The microchannel reactor is heated to 35 °C by a thermostatic bath circulator, and the residence time is maintained at 15 min. After the feed of the equipment is continuous and stable, 38.35 g of product is withdrawn per minute. By measuring the sample using the internal standard method, the condensation conversion rate of VE is 97.5%, and the yield is 95.1%;

[0069] (2) Take the product at the outlet of the microchannel reactor and separate acetic acid by vacuum distillation at 60 °C. The acetic acid content in the finished product of vitamin E acetate in the bottom of the distillation column at the separation end is about 0.3%; take the crude vitamin E acetate to the rectification column and perform vacuum rectification at 200 °C to obtain the finished vitamin E acetate with a purity of 98.1%, and the content of the finished product in the bottom of the column is 0.3%.

[0070] Example 14

[0071] (1) Dissolve 500 g of 2,3,5-trimethylhydroquinone diester in 100 g of acetic acid to form an acetic acid solution. Pump the acetic acid solution into the microchannel reactor loaded with modified resin F at a rate of 18.48 g / min and isophytol into the microchannel reactor at a rate of 30 g / min using a peristaltic pump. The microchannel reactor is heated to 35 °C by a thermostatic heating and cooling unit, and the residence time is maintained for 15 min. After the feed of the equipment is continuous and stable, 36.57 g of product is taken out per minute. The VE condensation conversion rate is 98.1% and the yield is 96.2% as measured by the internal standard method.

[0072] (2) Take the product at the outlet of the microchannel reactor and separate acetic acid by vacuum distillation at 60 °C. The acetic acid content in the finished product of vitamin E acetate in the bottom of the distillation column at the separation end is about 0.2%; take the crude vitamin E acetate to the rectification column and perform vacuum rectification at 200 °C to obtain the finished vitamin E acetate with a purity of 97.5%, and the content of the finished product in the bottom of the column is 0.2%.

[0073] Example 15

[0074] (1) Dissolve 500 g of 2,3,5-trimethylhydroquinone diester in 100 g of acetic acid to form an acetic acid solution. Pump the acetic acid solution into the microchannel reactor loaded with modified resin G at a rate of 18.48 g / min and isophytol into the microchannel reactor at a rate of 30 g / min using a peristaltic pump. The microchannel reactor is heated to 35 °C by a thermostatic heating and cooling unit, and the residence time is maintained for 15 min. After the feed of the equipment is continuous and stable, 37.69 g of product is taken out per minute. The VE condensation conversion rate is 95.3% and the yield is 97.1% as measured by the internal standard method.

[0075] (2) Take the product at the outlet of the microchannel reactor and separate acetic acid by vacuum distillation at 60 °C. The acetic acid content in the finished product of vitamin E acetate in the bottom of the distillation column at the separation end is about 0.6%; take the crude vitamin E acetate to the rectification column and perform vacuum rectification at 200 °C to obtain the finished vitamin E acetate with a purity of 95.4%, and the content of the finished product in the bottom of the column is 0.3%.

[0076] Example 16

[0077] (1) Dissolve 5000 g of trimethylhydroquinone diester in 1000 g of acetic acid to form an acetic acid solution. Pump the acetic acid solution and phytol at rates of 10 g / min and 16.23 g / min respectively into a microchannel reactor loaded with a catalyst using a peristaltic pump. The microchannel reactor is heated to 40 °C by a thermostatic bath circulator, and the residence time is maintained at 27 min. After the feed of the equipment is continuous and stable, 26.23 g of product is withdrawn per minute. By measuring the sample using the internal standard method, the condensation conversion rate of VE is 99.8% and the yield is 97.3%;

[0078] (2) Take the product at the outlet of the microchannel reactor and separate acetic acid under reduced pressure at 60 °C. The acetic acid content in the vitamin E acetate finished product at the bottom of the separation end is about 0.2%. Take the crude vitamin E acetate to a distillation column and perform vacuum distillation at 200 °C to obtain the finished vitamin E acetate with a purity of 99.5%, and the content of the finished product at the bottom of the column is 0.1%.

[0079] Comparative Example 3

[0080] (1) Dissolve 500 g of 2,3,5-trimethylhydroquinone diester in 100 g of acetic acid to form an acetic acid solution. Pump the acetic acid solution and phytol at rates of 18.48 g / min and 30 g / min respectively into a microchannel reactor loaded with modified resin A1 using a peristaltic pump. The microchannel reactor is heated to 35 °C by a thermostatic bath circulator, and the residence time is maintained at 15 min. After the feed of the equipment is continuous and stable, 38.48 g of product is withdrawn per minute. By measuring the sample using the internal standard method, the condensation conversion rate of VE is 75.6% and the yield is 90.5%;

[0081] (2) Take the product at the outlet of the microchannel reactor and separate acetic acid under reduced pressure at 60 °C. The acetic acid content in the vitamin E acetate finished product at the bottom of the separation end is about 2.9%. Take the crude vitamin E acetate to a distillation column and perform vacuum distillation at 200 °C to obtain the finished vitamin E acetate with a purity of 92.5%, and the content of the finished product at the bottom of the column is 2.5%.

[0082] Comparative Example 4

[0083] (1) Dissolve 500 g of 2,3,5-trimethylhydroquinone diester in 100 g of acetic acid to form an acetic acid solution. Pump the acetic acid solution and phytol at rates of 18.48 g / min and 30 g / min respectively into a microchannel reactor loaded with modified resin A2 using a peristaltic pump. The microchannel reactor is heated to 35 °C by a thermostatic bath circulator, and the residence time is maintained at 15 min. After the feed of the equipment is continuous and stable, 38.48 g of product is withdrawn per minute. By measuring the sample using the internal standard method, the condensation conversion rate of VE is 72.8% and the yield is 85.9%;

[0084] (2) Take the product at the outlet of the microchannel reactor and separate acetic acid by vacuum distillation at 60 °C. The acetic acid content in the vitamin E acetate finished product at the bottom of the separation end point is about 1.9%; take the crude vitamin E acetate to the rectification column and carry out vacuum rectification at 200 °C to obtain the finished vitamin E acetate with a purity of 90.8%, and the content of the finished product at the bottom of the column is 3.2%.

[0085] In summary, the prior art usually combines a protonic acid and a Lewis acid, uses trimethylhydroquinone as a substrate, and drops isophytol to complete the condensation reaction through a reaction kettle. The reaction residence time in this process is as long as 6-10 h, resulting in a relatively high vitamin E content, increasing the unit consumption of acetic anhydride esterification. Moreover, since a strong protonic acid and a Lewis acid are used as catalysts, the subsequent recovery and treatment of the catalysts are difficult, and there are more three-waste emissions; while the present invention uses a microchannel reactor filled with modified resin to carry out the condensation reaction, greatly shortening the reaction residence time to 2-10 min. The strong protonic acid and the Lewis acid are loaded onto the macroporous resin and filled into the microchannel reactor, reducing the post-treatment process of the condensation reaction liquid; and compared with the scheme of separately loading the strong protonic acid or the Lewis acid, the scheme of simultaneously loading the strong protonic acid and the Lewis acid onto the macroporous resin in the present invention can obtain a product with higher conversion rate and higher purity.

[0086] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same and similar parts among the various embodiments, reference can be made to each other. For the solutions disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and reference can be made to the description in the method part for the relevant parts.

[0087] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A preparation process of vitamin E acetate, characterized in that, using a modified resin as a catalyst, 2,3,5-trimethylhydroquinone diacetate as a solute, and acetic acid as a solvent, simultaneously pumping an acetic acid solution of 2,3,5-trimethylhydroquinone diacetate and phytol into a microchannel reactor for transesterification reaction to obtain vitamin E acetate; the catalyst is a resin loaded with a proton strong acid and a Lewis acid, and the catalyst is loaded in the microchannel reactor; the preparation method of the modified resin includes the following steps: (1) Taking a mixed solution of a proton strong acid and a Lewis acid dissolved in an organic solution, soaking a macroporous resin in the mixed solution until the macroporous resin is completely adsorbed; (2) Performing vacuum carbonization treatment on the completely adsorbed macroporous resin to obtain the modified resin; in step (1), the volume ratio of the mixed solution of the proton strong acid and the Lewis acid to the organic solution is 0.5 - 0.8:1; and / or the molar ratio of the proton strong acid to the Lewis acid is 1:1 - 1.

5.

2. The preparation process of vitamin E acetate according to claim 1, characterized in that, the organic solution is a mixed solution of an organic solvent and water, and the organic solvent includes any one or more of acetone, methanol, and ethanol; and / or the proton strong acid includes hydrobromic acid, hydrochloric acid, sulfuric acid, and the Lewis acid includes zinc chloride, zinc bromide, and zinc sulfate.

3. The preparation process of vitamin E acetate according to claim 1, characterized in that, in step (2), the temperature of the vacuum carbonization is 40 - 60 °C, and the vacuum degree is 60 - 100 KPa.

4. The preparation process of vitamin E acetate according to claim 1, characterized in that, the transesterification reaction time is 1 - 15 min, and the temperature is 35 - 50 °C.

5. The preparation process of vitamin E acetate according to claim 1, characterized in that, the mass ratio of 2,3,5-trimethylhydroquinone diacetate to acetic acid is 1:0.2 - 0.5, and the mass ratio of 2,3,5-trimethylhydroquinone diacetate to phytol is 1:1 - 1.

2.

6. The preparation process of vitamin E acetate according to any one of claims 1 - 5, characterized in that, further comprising: separating the vitamin E acetate from acetic acid and then performing rectification to obtain the finished product of vitamin E acetate.

7. The preparation process of vitamin E acetate according to claim 6, characterized in that, the vitamin E acetate and acetic acid are separated by vacuum distillation, and the separation temperature is 60 - 80 °C.

8. The preparation process of vitamin E acetate according to claim 6, characterized in that, the vitamin E acetate is purified by vacuum rectification, and the rectification purification temperature is 200 - 230 °C.

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