阅读说明：本技术 一种制备维生素e的方法 (Method for preparing vitamin E ) 是由 郭劲资 宋明焱 张涛 刘英瑞 程晓波 宋军伟 张弈宇 黎源 于 2020-05-28 设计创作，主要内容包括：本发明提供一种制备维生素E的方法。所述方法,包括以下步骤：在催化剂和助催化剂存在下,2,3,5-三甲基氢醌与异植物醇反应得到维生素E。所述催化剂为金属氧化物负载的杂多酸和有机膦化合物。所述有机膦化合物为叔膦化合物,优选三苯基膦。所用催化剂便于回收重复利用,对设备腐蚀小,产物稳定性好。能够抑制副产物生成,具有产物选择性高的特点。(The invention provides a method for preparing vitamin E. The method comprises the following steps: in the presence of catalyst and cocatalyst, 2,3, 5-trimethylhydroquinone reacts with isophytol to obtain vitamin E. The catalyst is heteropolyacid and organic phosphine compound loaded by metal oxide. The organic phosphine compound is a tertiary phosphine compound, preferably triphenylphosphine. The catalyst is convenient to recycle, has little corrosion to equipment and has good product stability. Can inhibit the generation of byproducts, and has the characteristic of high product selectivity.)

1. A method of preparing vitamin E comprising the steps of: in the presence of catalyst and cocatalyst, 2,3, 5-trimethylhydroquinone reacts with isophytol to obtain vitamin E.

2. The process of claim 1, wherein the catalyst is a metal oxide supported heteropolyacid and an organophosphinic compound.

3. The method of claim 2, wherein the metal oxide is selected from the group consisting of Fe₃O₄、α-Fe₂O₃、γ-Fe₂O₃、Co₂O₃、Co₃O₄Preferably Fe₃O₄。

4. A process according to claim 2 or 3, characterised in that the heteropolyacid is selected from H₃PW₁₂O₄₀、H₄PW₁₁VO₄₀、H₃PMo₁₂O₄₀、H₄SiW₁₂O₄₀、H₄PMo₁₁VO₄₀、H₄SiMo₁₂O₄₀、H₃PW₁₂O₄₀And H₄PMo₁₂O₄₀Preferably H₃PMo₁₂O₄₀、H₄PMo₁₁VO₄₀、H₄PMo₁₂O₄₀One or more of (a).

5. A process according to any one of claims 2-4, characterized in that the organic phosphine compound is a tertiary phosphine compound, preferably triphenylphosphine.

6. A process according to any one of claims 1 to 5, characterized in that the catalyst is used in an amount of 0.001 to 5 wt.%, preferably 0.01 to 3 wt.%, more preferably 0.05 to 2 wt.% of the amount of 2,3, 5-trimethylhydroquinone.

7. A process according to any one of claims 1 to 6, wherein the promoter is one or more of phenyl ortho-hydroxybenzoate, methyl hydroxybenzoate and ethyl benzoate.

8. A process according to any one of claims 1 to 7, characterized in that the cocatalyst is present in an amount of 0.0001 to 1 wt.%, preferably 0.001 to 0.3 wt.%, relative to the amount of 2,3, 5-trimethylhydroquinone.

9. The method according to any one of claims 1 to 8, wherein the molar ratio of 2,3, 5-trimethylhydroquinone to isophytol is 1 (0.8-2); preferably 1 (0.9-1.1).

10. The process according to any one of claims 1 to 9, wherein the catalyst is prepared by a process comprising the steps of: according to the proportion of the components,

1) ultrasonically oscillating metal oxide and heteropoly acid in a solvent for 2-10h, then soaking for 8-12h, and roasting the separated solid at the temperature of 600-1300 ℃ for 2-16h to obtain an intermediate carrier;

2) mixing and stirring an organic phosphine compound and fatty alcohol for 1-10h, then mixing with the intermediate carrier prepared in the step 1), carrying out ultrasonic treatment at room temperature for 0.5-4h, washing the separated solid with the fatty alcohol, and drying at 70-110 ℃ for 4-12h under the condition of nitrogen to obtain the catalyst.

Technical Field

The invention belongs to the field of fine chemical synthesis, and particularly relates to a preparation method of vitamin E.

Background

Vitamin E (vitamin E or VE) is one of the first discovered vitamins, and since the first discovery in the 20 th of the 19 th century, the production and application thereof have been the research hotspots in the vitamin field. Vitamin E is used as an efficient antioxidant and has wide application in the fields of food, cosmetics, feed and the like. Vitamin E is classified into natural VE and synthetic VE. 80% of the vitamin E obtained by people comes from synthetic vitamin E, which refers to alpha-tocopherol, while natural vitamin E only accounts for about 20%. At present, almost all the chemical synthesis of vitamin E in industry is carried out by taking trimethylhydroquinone and isophytol as raw materials and carrying out condensation reaction.

Chinese patent CN103396392A provides a method for preparing vitamin E by using 2,3, 5-trimethylhydroquinone and isophytol through reaction under the condition of magnesium oxide supported silica as a catalyst. In the preparation process, two raw materials, namely 2,3, 5-trimethylhydroquinone and isophytol, are simultaneously put into a reaction system at one time, but the isophytol is unstable, so that the risk of converting the isophytol into other impurities is increased.

European patent EP603695 provides the synthesis of vitamin E by condensation of trimethylhydroquinone and isophytol in a liquid or supercritical carbon dioxide system using acidic catalysts hydrochloric acid, zinc chloride and an ion exchanger as catalysts. The operation process of the process is complex, the catalyst is difficult to recycle, and the problems of serious equipment corrosion and troublesome waste liquid treatment exist.

In the US6369242, trifluoromethanesulfonic acid is used as a catalyst to catalytically synthesize alpha-tocopherol, and in the method, because trifluoromethanesulfonic acid has strong acidity, isophytol is easily dehydrated at high temperature to generate a byproduct, which affects the product yield, and in the strong acid condition, the requirement on production equipment is high, so that the method is not suitable for industrial production.

Chinese patent CN105820149A provides a method for preparing alpha-tocopherol by using metal catalyst. The method comprises the step of reacting 2,3, 5-trimethylhydroquinone with isophytol in the presence of a solvent and a metal catalyst to generate alpha-tocopherol, wherein the molar ratio of the 2,3, 5-trimethylhydroquinone to the isophytol is 5:1 to 2: 1. The raw material 2,3, 5-trimethylhydroquinone is greatly excessive, and the 2,3, 5-trimethylhydroquinone needs to be recycled after the reaction is finished, so that the energy consumption for reaction and separation is increased.

In conclusion, the existing method for preparing vitamin E has the problems of easy deterioration of raw materials, complex process operation process, difficult recycling and reusing of the catalyst, serious corrosion of equipment, troublesome waste liquid treatment, increased energy consumption for reaction and separation and the like. Therefore, a new method for preparing vitamin E is needed to solve the above technical problems.

Disclosure of Invention

The invention provides a method for preparing vitamin E, which has the advantages of low selectivity of byproducts, high selectivity of products, small using amount of catalyst, easy recovery of catalyst, high utilization rate of raw materials, environmental protection, small corrosion to equipment and the like.

The invention also provides a catalyst and cocatalyst system for preparing vitamin E. High catalytic efficiency, inhibiting by-products and high product selectivity.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a method for preparing vitamin E, which comprises the step of reacting 2,3, 5-Trimethylhydroquinone (TMHQ) with Isophytol (IPL) in the presence of a catalyst and a cocatalyst to obtain Vitamin E (VE).

In the invention, the structural formulas of the 2,3, 5-Trimethylhydroquinone (TMHQ) and the Isophytol (IPL) are shown as follows:

the structural formula of the target product vitamin E is shown as follows:

preferably, the method of the present invention is carried out in the presence of a solvent, wherein the solvent is one or more of n-pentane, n-hexane, cyclohexane, n-heptane, petroleum ether, toluene, benzene, and xylene. The mass ratio of the solvent to the 2,3, 5-trimethylhydroquinone is 1:1-10:1, more preferably 2:1-6: 1.

The catalyst is a metal oxide supported heteropoly acid and an organic phosphine compound.

In the catalyst of the present invention, the metal oxide: the mass ratio of the heteropoly acid is 100: (20-80), preferably 100: (30-60). An organic phosphine compound: the mass ratio of the metal oxide to the sum of the heteropoly acid is (0.03-10): 100, preferably (0.1-5), 100, and the catalyst with the preferable composition proportion is adopted, and the components can be better cooperated, so that the higher catalytic activity and better catalytic effect of the catalyst can be ensured.

The metal oxide of the present invention is selected from Fe₃O₄、α-Fe₂O₃、γ-Fe₂O₃、Co₂O₃、Co₃O₄One or more of the metal oxides, preferably Fe₃O₄。

The catalyst provided by the invention can uniformly disperse active components such as heteropoly acid and organic phosphine on the metal oxide carrier, so that the reaction is convenient to carry out, and the catalyst has better strength and longer service life.

The heteropoly acid of the invention is selected from H₃PW₁₂O₄₀、H₄PW₁₁VO₄₀、H₃PMo₁₂O₄₀、H₄SiW₁₂O₄₀、H₄PMo₁₁VO₄₀、H₄SiMo₁₂O₄₀、H₃PW₁₂O₄₀And H₄PMo₁₂O₄₀Preferably the heteropolyacid is H₃PMo₁₂O₄₀、H₄PMo₁₁VO₄₀、H₄PMo₁₂O₄₀Experiments prove that the preferable heteropoly acid can reduce the deterioration rate of the raw material Isophytol (IPL) in the reaction process, thereby ensuring that the isophytol can be efficiently used for the main reaction.

The organophosphinic compound of the present invention is preferably a tertiary phosphine compound, more preferably triphenylphosphine.

The catalyst according to the invention is used in an amount of 0.001 to 5 wt.%, preferably 0.01 to 3 wt.%, more preferably 0.05 to 2 wt.%, relative to the amount of TMHQ (2,3, 5-trimethylhydroquinone) substrate.

The cocatalyst is one or more of phenyl o-hydroxybenzoate, methyl hydroxybenzoate and ethyl benzoate.

The cocatalyst according to the invention is used in an amount of 0.0001 to 1 wt%, preferably 0.001 to 0.3 wt%, relative to the amount of TMHQ (2,3, 5-trimethylhydroquinone) substrate.

The molar ratio of the 2,3, 5-trimethylhydroquinone to the isophytol is 1: (0.8-2); preferably 1 (0.9-1.1).

The 2,3, 5-trimethylhydroquinone and the isophytol are reacted at the temperature of 20-100 ℃, preferably at the temperature of 40-70 ℃; if the reaction temperature is too low, the reaction rate is slow, the IPL as a raw material has the risk of deterioration, and the time cost is increased; if the reaction temperature is too high, the selectivity of the product is reduced; in the above preferred temperature range, the reaction can be completed in 2-10h, and the conversion rate of the TMHQ raw material is higher than 99%.

Preferably, when the vitamin E is prepared, the two raw materials, namely the 2,3, 5-trimethylhydroquinone and the isophytol, are fed in a sequence that one raw material is added into a reaction system, and then the other raw material is added dropwise; for example, 2,3, 5-trimethylhydroquinone is initially charged into the reaction system, while isophytol is then added dropwise to the reaction system.

A method of preparing the catalyst of the present invention comprises the steps of: according to the proportion of the components,

1) ultrasonically oscillating metal oxide and heteropoly acid in a solvent for 2-10h, then soaking for 8-12h, and roasting the separated solid at the temperature of 600-1300 ℃ for 2-16h to obtain an intermediate carrier;

2) mixing and stirring an organic phosphine compound and fatty alcohol for 1-10h, then mixing with the intermediate carrier prepared in the step 1), carrying out ultrasonic treatment at room temperature for 0.5-4h, washing the separated solid with the fatty alcohol, and drying at 70-110 ℃ for 4-12h under the condition of nitrogen to obtain the catalyst.

Preferably, step 1) and step 2) of the present invention are performed under the protection of inert gas.

The solvent in step 1) of the present invention is preferably water and/or ethanol, and the mass of the solvent is 3 to 30 times of the mass of the metal oxide.

In the step 1) of the invention, the mass ratio of the metal oxide to the heteropoly acid is 100 (20-80), preferably 100: (30-60).

In the step 2), the mass ratio of the intermediate carrier to the organic phosphine compound is 100: (0.03-10), preferably the mass ratio is 100 (0.1-5).

The fatty alcohol in step 2) of the present invention is preferably methanol and/or ethanol.

In the process of the invention, the catalyst used has the following characteristics: the metal oxide is used as a carrier of the catalyst, and the heteropoly acid and the organic phosphine compound are loaded on the metal oxide to be used as active components. Active component heteropoly acid as one kind

The acid has higher reactivity for the reaction, can promote the reaction to be carried out under milder conditions, and simultaneously, the heteropoly acid has no pollution to the environment after being loaded and does not corrode equipment. The organic phosphine compound is preferably a tertiary phosphine compound, can form an amphoteric active substance with heteropoly acid in a reaction system by utilizing the alkalescence of the organic phosphine compound, has an acid-base regulation effect on a catalytic system, can consume an oxidizing substance in the reaction system, can inhibit the oxidation of the raw material isophytol to generate an oxidizing impurity shown in the formula I, and further improves the selectivity of a main product.

The catalytic system of the invention consists of the catalyst and the cocatalyst, and has the characteristics of high product selectivity, small catalyst dosage, easy catalyst recovery, high raw material utilization rate, environmental protection, small corrosion to equipment and the like.

The cocatalyst disclosed by the invention has an inhibiting effect on main impurities (formula II) in the reaction process, has a certain effect of increasing the steric hindrance of the carbon-carbon double bond of the isophytol in the reaction process, and further inhibits the combination of the No. 2 position of the carbon-carbon double bond of the isophytol and TMHQ to form a main impurity compound of formula II, so that the combination of the No. 1 position of the carbon-carbon double bond of the isophytol and TMHQ is ensured to form a reaction product vitamin E.

Compared with the catalyst in the prior art, such as zinc halide, halogen acid and the like, the catalyst adopted in the method for preparing the Vitamin E (VE) can better solve the problems of Lewis acid and Vitamin E (VE)

The method has the characteristics of high product selectivity, small catalyst consumption, easy catalyst recovery, high raw material utilization rate, environmental protection, small corrosion to equipment and the like.

The selectivity of the main product vitamin E prepared by the method can reach more than 99 percent, and the total yield of the product can reach more than 98 percent.

Detailed Description

In order to better understand the technical solution of the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.