Extraction process of low-loss vitamin E

Abstract

The invention relates to the field of vitamin E extraction processes, in particular to an extraction process of low-loss vitamin E. The extraction process comprises the following steps: acidic esterification, alkaline esterification, hydrolysis, cold separation and molecular distillation. Wherein in the step of acidic esterification, DD oil, concentrated sulfuric acid, methanol and a protective agent are mixed and then heated to react for 0.5-1 h, and the protective agent comprises at least one of methoxyl-polyethylene glycol-carboxyl and acetic acid; and hydrolysis: mixing the alkaline ester with concentrated sulfuric acid and methanol, and heating to react for 1-1.5 hours. Vitamin E is converted into vitamin E ester before alkaline esterification through distribution of the steps of acidic esterification, alkaline esterification and hydrolysis, the risk that vitamin E is degraded in an alkaline environment is reduced, then vitamin E ester is decomposed into vitamin E again through concentrated sulfuric acid catalysis for a longer time after alkaline esterification, and the quality of vitamin E is improved. Therefore, the damage of the alkaline environment to the vitamin E is reduced while the plasticizer is degraded.

Description

Technical Field

[0001] This application relates to the field of vitamin E extraction processes, and specifically relates to an extraction process for low-loss vitamin E. Background Art

[0002] Deodorizer distillate (DD oil) is an important raw material for concentrated natural vitamin E (VE). It has a complex composition and mainly contains VE, sterols, triglycerides, free fatty acids, etc. The acid-catalyzed esterification process is the main method for industrialized concentration of natural VE at present. Through the esterification method, fatty acids are reacted to form fatty acid methyl esters, and then further separation is carried out by means of molecular distillation, supercritical CO2 fluid extraction, etc.

[0003] Plasticizers, also known as plasticizers or plasticizing agents, are additives for polymer materials. Adding them to polymer materials can increase the plasticity of the polymer. They are mainly used in the production of various plastic products, such as food packaging materials, toys, medical blood bags, medical rubber hoses, vinyl floors, etc. The main components of plasticizers are phthalic acid esters, such as di-n-butyl phthalate (abbreviation DBP), bis(2-ethylhexyl) phthalate (abbreviation DEHP), diisononyl phthalate (abbreviation DINP), etc. In conventional transportation, DD oil is mostly stored in ordinary plastic barrels. Since plasticizers are fat-soluble compounds, they are more likely to migrate into DD oil during transportation. However, plasticizers are highly toxic to humans and organisms. Therefore, during the process of concentrated natural VE, during the acid-catalyzed esterification process, an alkaline solution also needs to be added to hydrolyze the plasticizer and remove it. However, since VE is unstable in an alkaline environment and is prone to degradation or isomerization reactions, its content will be reduced. Summary of the Invention

[0004] In order to solve the problem that VE is also easily degraded when using an alkaline solution to remove plasticizers during the process of concentrated natural VE, this application provides an extraction process for low-loss vitamin E. This extraction process is carried out through steps of acidic esterification - alkaline esterification - hydrolysis, enabling vitamin E to be converted into vitamin E ester before alkaline esterification, reducing the risk of vitamin E degradation in an alkaline environment. Then, after alkaline esterification, it is catalyzed by concentrated sulfuric acid for a longer time to decompose vitamin E ester back into vitamin E, reducing the damage to vitamin E in an alkaline environment while degrading plasticizers.

[0005] This application provides an extraction process for low-loss vitamin E, adopting the following technical scheme: An extraction process for low-loss vitamin E, comprising the following steps: Acidic esterification: Mix DD oil, concentrated sulfuric acid, methanol, and a protective agent and heat them for reaction for 0.5 - 1 h to obtain an acidic esterification mixture; the protective agent includes at least one of methoxy-polyethylene glycol-carboxyl and acetic acid; Alkaline esterification: After washing the acidic esterification mixture with water, it is mixed with sodium methoxide and methanol and then heated for reaction to obtain an alkaline esterification mixture; Hydrolysis: After washing the alkaline esterification mixture with water, it is mixed with concentrated sulfuric acid and methanol and then heated for reaction for 1 - 1.5 h to obtain a hydrolysis mixture; Cold precipitation: After washing the hydrolysis mixture with water, it is subjected to cold precipitation, and the precipitate is removed to obtain a cold - precipitated mixture; Molecular distillation: The cold - precipitated mixture is subjected to molecular distillation to obtain crude VE.

[0006] By adopting the above - mentioned technical solution, in this application, a protective agent is added in the acidic esterification step. Under the catalysis of concentrated sulfuric acid, it reacts with vitamin E to form an ester substance, forming a stable ester - bond structure. The generated vitamin E ester is more stable in the subsequent alkaline environment. Sodium methoxide (strongly alkaline) undergoes a saponification reaction with the plasticizer (such as phthalate esters) in the acidic esterification mixture, decomposing it into low - toxicity substances (such as sodium phthalate), and removing it by washing with water.

[0007] In the hydrolysis stage, during the long - time reaction of 1 - 1.5 h with concentrated sulfuric acid, concentrated sulfuric acid will damage the structure of vitamin E ester, causing it to degrade and releasing vitamin E. This facilitates obtaining more vitamin E during subsequent molecular distillation. Since it is under concentrated sulfuric acid for a long time, the structure of vitamin E ester will decompose. Therefore, the reaction time for hydrolysis needs to be longer than that for acidic esterification.

[0008] Through the step distribution of acidic esterification - alkaline esterification - hydrolysis in this application, vitamin E is converted into vitamin E ester before alkaline esterification, reducing the risk of vitamin E degradation in the alkaline environment. Then, after alkaline esterification, through longer - time catalysis by concentrated sulfuric acid, vitamin E ester is decomposed back into vitamin E, reducing the damage to vitamin E in the alkaline environment while degrading the plasticizer.

[0009] Preferably, the protective agent is methoxy - polyethylene glycol - carboxyl.

[0010] By adopting the above - mentioned technical solution, through separate comparison of the two protective agents, it is found that methoxy - polyethylene glycol - carboxyl has the best effect. The reason is that methoxy - polyethylene glycol - carboxyl can not only react with vitamin E to form vitamin E ester, but also the polyethylene glycol structure of methoxy - polyethylene glycol - carboxyl can encapsulate the hydrophobic structure of vitamin E, thus better improving the stability of vitamin E in the alkaline environment. While acetic acid and vitamin E can only form vitamin E ester and cannot encapsulate the hydrophobic structure of vitamin E. Therefore, the structural stability of vitamin E acetate is inferior to that of the ester substance formed by methoxy - polyethylene glycol - carboxyl. Therefore, comparatively speaking, methoxy - polyethylene glycol - carboxyl has better comprehensive performance.

[0011] Preferably, the protective agent is acetic acid. Further, in the step of alkaline esterification, the acidic esterification mixture is washed with water, then β-cyclodextrin solution is added, heated and mixed, and then filtered to obtain a mixture. Then, sodium methoxide and methanol are added to the mixture, heated and reacted to obtain an alkaline esterification mixture.

[0012] By adopting the above technical solution, when acetic acid and vitamin E form vitamin E acetate, β-cyclodextrin can encapsulate the hydrophobic structure of vitamin E acetate, effectively improving the stability of vitamin E acetate in an alkaline environment. During hydrolysis, concentrated sulfuric acid breaks the cyclic glycosidic bond of β-CD, resulting in the dissociation of the inclusion complex and the release of VE. Compared with the ester structure formed by methoxy-polyethylene glycol-carboxyl and vitamin E, concentrated sulfuric acid can decompose β-cyclodextrin more easily, making it easier for vitamin E to be released. Therefore, acetic acid and β-cyclodextrin can better improve the preservation amount of vitamin E.

[0013] Preferably, the mass ratio of the DD oil to the β-cyclodextrin is 100:15 - 18.

[0014] By adopting the above technical solution, when the content of β-cyclodextrin is too low, β-cyclodextrin has insufficient inclusion of vitamin E acetate, resulting in limited improvement in its stability in an alkaline environment; when the content of β-cyclodextrin is too high, β-cyclodextrin can already fully encapsulate vitamin E acetate, and it is difficult to further improve the stability of vitamin E acetate. Therefore, after a large amount of research and experimental verification by the applicant, it is finally determined that the mass ratio of the DD oil to the β-cyclodextrin in this application is preferably as above.

[0015] Preferably, in the step of acidic esterification, the weight parts of each component are 100 parts of DD oil, 3 - 4 parts of concentrated sulfuric acid, 20 parts of methanol, and 7 - 10 parts of protective agent.

[0016] Preferably, in the step of hydrolysis, the weight part of concentrated sulfuric acid is 4 - 8 parts, and the weight part of methanol is 30 parts.

[0017] Preferably, in the step of alkaline esterification, the weight part of sodium methoxide is 4 - 5 parts, and the weight part of methanol is 20 parts.

[0018] Preferably, in the step of hydrolysis, the weight part of concentrated sulfuric acid is 6 - 8 parts.

[0019] By adopting the above technical solution, since in the step of hydrolysis, concentrated sulfuric acid not only needs to continue to complete the esterification reaction, but also decompose the ester substances formed by the protective agent and vitamin E, the content of concentrated sulfuric acid in the hydrolysis step needs to be higher than that in the acidic esterification step.

[0020] In summary, the present application has the following beneficial effects: 1. Due to the step distribution of acid esterification - alkaline esterification - hydrolysis in this application, vitamin E is converted into vitamin E ester before alkaline esterification, reducing the risk of vitamin E degradation in an alkaline environment. Then, after alkaline esterification, vitamin E ester is decomposed back into vitamin E through longer - time catalysis with concentrated sulfuric acid, reducing the damage to vitamin E by the alkaline environment while degrading the plasticizer. 2. This application adopts the combination of acetic acid and β - cyclodextrin. Among them, acetic acid combines with vitamin E to form vitamin E acetate, and β - cyclodextrin contains vitamin E acetate, further improving the stability of vitamin E ester in an alkaline environment. And compared with methoxy - polyethylene glycol - carboxyl, β - cyclodextrin is more easily destroyed by concentrated sulfuric acid, thus further improving the extraction rate of vitamin E. Specific embodiments

[0021] The raw materials in this application include the following parts: Methoxy - polyethylene glycol - carboxyl: A commercially available product with a CAS number of 67665 - 18 - 3 and a molecular weight specification of 400. β - Cyclodextrin: A commercially available product with a CAS number of 68168 - 23 - 0.

[0022] The following further elaborates on this application in combination with examples and comparative examples.

[0023] Example 1 An extraction process for vitamin E with low loss, including the following steps: Acid esterification: 1000 g of DD oil, 40 g of concentrated sulfuric acid, 200 g of methanol, and 100 g of methoxy - polyethylene glycol - carboxyl are mixed and heated for reaction for 0.8 h at a heating temperature of 80 °C to obtain an acid - esterified mixture. Alkaline esterification: The acid - esterified mixture is washed with water, and after standing and separating layers, the acidic waste water is removed. Then it is mixed with 50 g of sodium methoxide and 200 g of methanol and heated for reaction for 2 h at a heating temperature of 80 °C to obtain an alkaline - esterified mixture. Hydrolysis: After the alkaline esterified product is washed with water, and after standing and separating layers, the alkaline waste water is removed. Then it is mixed with 80 g of concentrated sulfuric acid and 300 g of methanol and heated for reaction for 1.2 h to obtain a hydrolyzed mixture. Cold precipitation: The hydrolyzed mixture is washed with water and then subjected to cold precipitation at a cold precipitation temperature of 4 °C for 4 h. After removing the precipitated matter, a cold - precipitated mixture is obtained. Molecular distillation: The cold - precipitated mixture is subjected to molecular distillation. The conditions for molecular distillation are a vacuum degree of 0.5 Pa, a temperature of 220 °C, a scraper rotation speed of 120 r / min, and a time of 3 h to obtain crude VE.

[0024] Examples 2 - 3 Example 2-3 Based on the preparation method of Example 1, the reaction time in the acidic esterification step (hereinafter referred to as "acid reaction time") and the reaction time in the hydrolysis step (hereinafter referred to as "hydrolysis reaction time") were adjusted. The specific adjustments are shown in Table 1.

[0025] Comparative Examples 1-3 Comparative Example 1 Based on the preparation method of Example 1, 100 g of methoxy-polyethylene glycol-carboxyl was not added in the acidic esterification step.

[0026] Comparative Example 2 Based on the preparation method of Example 1, 100 g of methoxy-polyethylene glycol-carboxyl was not added in all steps. And the reaction time in the acidic esterification step was adjusted to 2 h, the hydrolysis step was not carried out, and the basic esterification mixture was directly washed with water and then subjected to cold precipitation.

[0027] Comparative Example 3 Based on the preparation method of Example 1, the reaction time in the acidic esterification step and the reaction time in the hydrolysis step were adjusted. The specific adjustments are shown in Table 1.

[0028] The crude VE of Examples 1-3 and Comparative Examples 1-3 was subjected to the following performance detection tests.

[0029] Performance Detection Tests 1. Plasticizer Content According to GB / T 21911-2008 Determination of Phthalates in Foods, the content of plasticizer was determined.

[0030] 2. Extraction Rate The extraction rate of vitamin E = (B / A) * 100%, where A represents the mass (g) of vitamin E in DD oil, and B represents the mass (g) of vitamin E in crude VE.

[0031] Table 1 Reaction Time in the Initial Acidic Esterification Step, Reaction Time in the Re-Acidic Esterification Step, and Performance Detection Table of Examples 1-3 and Comparative Examples 1-3

[0032] Referring to Table 1, by comparing Examples 1-3 and Comparative Examples 1-3, it can be seen that Comparative Examples 1-2 illustrate that without methoxy-polyethylene glycol-carboxyl, whether the reaction time of the acidic esterification step is set to 2 h and the hydrolysis step is not carried out; or the reaction time of the acidic esterification step is set to 0.8 h and the subsequent hydrolysis step reaction time is set to 1.2 h, it does not affect the removal of plasticizers. The comparison between Example 1 and Comparative Example 1 shows that methoxy-polyethylene glycol-carboxyl can effectively improve the stability of vitamin E during the extraction process. Possibly because adding methoxy-polyethylene glycol-carboxyl in the acidic esterification step can form ester substances with vitamin E, which are more stable in the subsequent alkaline environment. In the hydrolysis stage, under the reaction of concentrated sulfuric acid for 1-1.5 h, the structure of vitamin E ester will be damaged and degraded, releasing vitamin E, which is convenient for obtaining more vitamin E during subsequent molecular distillation.

[0033] Compared with Examples 1-3 and Comparative Example 3, it can be found that the extraction rate of vitamin E in Example 1 is the highest. Possibly because in the acidic esterification step, the reaction time is too short, the catalytic effect of concentrated sulfuric acid is incomplete, and not enough ester substances are formed between vitamin E and methoxy-polyethylene glycol-carboxyl, so vitamin E is easily decomposed in the subsequent alkaline esterification. If the reaction time is too long, concentrated sulfuric acid will damage the already formed ester substances and destroy the protective effect of methoxy-polyethylene glycol-carboxyl. In the hydrolysis step, if the reaction time is too short, the ester substances are not decomposed, which will affect the extraction amount of vitamin E during subsequent molecular distillation. If the reaction time is too long, the ester substances have been fully decomposed and there is no need to continue extending the time. Therefore, Example 1 is taken as the preferred one.

[0034] Examples 4-5 Based on the preparation method of Example 1, in Example 4, 100 g of methoxy-polyethylene glycol-carboxyl was replaced with 100 g of acetic acid.

[0035] Based on the preparation method of Example 1, in Example 5, 100 g of methoxy-polyethylene glycol-carboxyl was replaced with 100 g of acetic acid; The alkaline esterification step was adjusted as follows: The acidic esterification mixture was washed with water, and after standing and separating, the acidic wastewater was removed. Then, a saturated aqueous solution of β-cyclodextrin was added, and the content of β-cyclodextrin in the saturated aqueous solution of β-cyclodextrin was 180 g. After heating and mixing, filtration was carried out. The heating temperature was 60 °C and the heating time was 3 h to obtain a mixture-containing solution; The mixture-containing solution was mixed with 50 g of sodium methoxide and 200 g of methanol and then heated and reacted for 2 h at a heating temperature of 80 °C to obtain an alkaline esterification mixture.

[0036] The crude VE of Examples 4-5 was subjected to the above performance tests, and the test results are shown in Table 2.

[0037] Table 2 Data table of the types of protective agents, addition of β-cyclodextrin, and performance detection in Example 1 and Examples 4 - 5

[0038] Referring to Table 2, by comparing Example 1 with Examples 4 - 5, it can be seen that both methoxy-polyethylene glycol-carboxyl and acetic acid can be used in this application, and the methoxy-polyethylene glycol-carboxyl has better comprehensive performance. The reason is that methoxy-polyethylene glycol-carboxyl can not only form vitamin E ester with vitamin E, but also the polyethylene glycol structure of methoxy-polyethylene glycol-carboxyl can contain the hydrophobic structure of vitamin E, thus better improving the stability of vitamin E in an alkaline environment. While acetic acid and vitamin E can only form vitamin E ester and cannot contain the hydrophobic structure of vitamin E. Therefore, the structural stability of vitamin E acetate is inferior to the ester substances formed by methoxy-polyethylene glycol-carboxyl.

[0039] However, by first heating and mixing the acidic esterification mixture with β-cyclodextrin, β-cyclodextrin can contain the hydrophobic structure of vitamin E acetate, effectively improving the stability of vitamin E acetate in an alkaline environment. During the hydrolysis process, concentrated sulfuric acid destroys the cyclic glycosidic bond of β-cyclodextrin, resulting in the dissociation of the inclusion complex and the release of VE. And compared with the ester structure formed by methoxy-polyethylene glycol-carboxyl and vitamin E, concentrated sulfuric acid can decompose β-cyclodextrin more easily, making vitamin E easier to separate. Therefore, the effect of the combination of acetic acid and β-cyclodextrin is superior to that of methoxy-polyethylene glycol-carboxyl.

[0040] Examples 6 - 9 Based on the preparation method of Example 5, Examples 6 - 9 adjusted the content of β-cyclodextrin in the β-cyclodextrin solution, and the specific adjustment is shown in Table 3.

[0041] The crude VE of Examples 6 - 9 was subjected to the above performance detection, and the test results are shown in Table 3.

[0042] Table 3 Data table of β-cyclodextrin content and performance detection in Examples 4 - 9

[0043] Referring to Table 3, by comparing Examples 4 - 9, it can be seen that as the addition amount of β-cyclodextrin continuously increases, the extraction rate of vitamin E continuously rises until it levels off. This may be because β-cyclodextrin continuously includes vitamin E acetate, and the stability of vitamin E acetate continuously increases until it levels off, thereby continuously increasing the extraction rate of vitamin E.

[0044] Examples 10 - 13 Examples 10 - 13 Based on the preparation method of Example 1, the contents of concentrated sulfuric acid and methoxy-polyethylene glycol-carboxyl in the acidic esterification step, and the content of sodium methoxide in the basic esterification step were adjusted. The specific adjustments are shown in Table 4.

[0045] The crude VE of Examples 10 - 13 was subjected to the above performance tests, and the test results are shown in Table 4.

[0046] Table 4 Data table of component contents and performance tests of Example 1 and Examples 10 - 13

[0047] Referring to Table 4, by comparing Example 1 and Examples 10 - 13, it can be seen that with the above ratios in the acidic esterification, they can all be used in this application.

[0048] Examples 14 - 17 Examples 14 - 17 Based on the preparation method of Example 1, the concentrated sulfuric acid in the hydrolysis step was adjusted. The specific adjustments are shown in Table 5.

[0049] The crude VE of Examples 14 - 17 was subjected to the above performance tests, and the test results are shown in Table 5.

[0050] Table 5 Data table of concentrated sulfuric acid in the hydrolysis step and performance tests of Example 1 and Examples 14 - 17

[0051] Referring to Table 5, by comparing Example 1 and Examples 14 - 17, it can be seen that in the hydrolysis step, concentrated sulfuric acid not only needs to continue to complete the esterification reaction, but also decompose the esters formed by the protective agent and vitamin E. Since the content of methoxy-polyethylene glycol-carboxyl in the acidic esterification is relatively high, in the hydrolysis step, the content of concentrated sulfuric acid is higher than that in the acidic esterification step, which is beneficial to improving the extraction rate of vitamin E.

[0052] This specific embodiment is only an explanation of this application, and it is not a limitation of this application. After reading this specification, those skilled in the art can make modifications without creative contributions to this embodiment as needed, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. An extraction process for low-loss vitamin E, characterized in that, It includes the following steps: Acidic esterification: Mix DD oil, concentrated sulfuric acid, methanol and a protective agent, and then heat and react for 0.5 - 1 h to obtain an acidic esterification mixture; the protective agent includes at least one of methoxy-polyethylene glycol-carboxyl and acetic acid; Basic esterification: After washing the acidic esterification mixture with water, mix it with sodium methoxide and methanol, and then heat and react to obtain a basic esterification mixture; Hydrolysis: After washing the basic esterification mixture with water, mix it with concentrated sulfuric acid and methanol, and then heat and react for 1 - 1.5 h to obtain a hydrolysis mixture; Cold precipitation: After washing the hydrolysis mixture with water, perform cold precipitation, and remove the precipitated substances to obtain a cold-precipitated mixture; Molecular distillation: Perform molecular distillation on the cold-precipitated mixture to obtain crude VE.

2. The extraction process of low-loss vitamin E according to claim 1, characterized in that: The protective agent is methoxy-polyethylene glycol-carboxyl.

3. The extraction process of low-loss vitamin E according to claim 1, characterized in that: The protective agent is acetic acid. It also includes that in the step of basic esterification, wash the acidic esterification mixture with water, then add a β-cyclodextrin solution, heat and mix, and then filter to obtain a contained mixture. Then add sodium methoxide and methanol to the contained mixture, mix and heat and react to obtain a basic esterification mixture.

4. The extraction process of low-loss vitamin E according to claim 3, characterized in that: The mass ratio of the DD oil to the β-cyclodextrin is 100:15 - 18.

5. The extraction process of low-loss vitamin E according to claim 1, characterized in that: In the step of acidic esterification, the weight parts of each component are 100 parts of DD oil, 3 - 4 parts of concentrated sulfuric acid, 20 parts of methanol and 7 - 10 parts of the protective agent.

6. The extraction process of low-loss vitamin E according to claim 5, characterized in that: In the step of basic esterification, the weight part of sodium methoxide is 4 - 5 parts, and the weight part of methanol is 20 parts.

7. The extraction process of low-loss vitamin E according to claim 6, characterized in that: In the step of hydrolysis, the weight part of concentrated sulfuric acid is 4 - 8 parts, and the weight part of methanol is 30 parts.

8. The extraction process of low-loss vitamin E according to claim 6, characterized in that: In the step of hydrolysis, the weight part of concentrated sulfuric acid is 6 - 8 parts.

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