Preparation method of vitamin A acetate

A technology of acetate and vitamin, which is applied in the field of preparation of vitamin A acetate, can solve the problems of slow elimination and decomposition reaction of intermediates, difficult post-processing, poor selectivity, etc., and achieve long-term stable storage, oxidation resistance and thermal stability. The effect of good stability and good market competitiveness

Pending Publication Date: 2021-08-06
WANHUA CHEM GRP CO LTD
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Problems solved by technology

This method reduces the use and separation of solvents, but requires the use of highly hazardous reagents such as sodium methoxide, sodium ethoxide, potassium tert-butoxide, or sodium hydride, which require high air and moisture control, and the atomic utilization of the two-step Wittig reagent The rate is lower, both 20%
[0005] CN101219983A discloses an improved preparation method of vitamin A acetate, through the Wittig reaction of carbon pentaphosphonic acid dialkyl ester and 4-acetoxy-2-methyl-2-butene-1 aldehyde as raw material The target product is obtained, and the reaction solvent is a mixture of toluene and pyridine (or methyl-substituted pyridine), so that the reaction is carried out in an environment close to room temperature; however, the method needs to use high-risk reagents such as sodium methylate and sodium ethylate, and The isomer selectivity of the product is poor
In this method, the preparation reaction temperature of the C15 phosphine salt is difficult to control, a large am

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  • Preparation method of vitamin A acetate
  • Preparation method of vitamin A acetate
  • Preparation method of vitamin A acetate

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preparation example Construction

[0077] In the preparation method of vitamin A acetate of the present invention, reaction formula is as follows:

[0078]

Embodiment 1

[0081] A kind of preparation method of vitamin A acetate, process flow chart is as figure 1 As shown, the specific steps are as follows:

[0082] (1) Add 106g sodium carbonate solid powder in the first raw material tank 1, add 1060mL water under stirring state, mix and obtain material B; Add 501.08g C15 phosphine salt, 142g C5 aldehyde in the second raw material tank 10, stir state Add 2500mL of mixed solvent (the volume ratio of water, methanol and n-hexane is 100:1:10), mix well to obtain material A, and nitrogen blanket for use;

[0083] (2) Reactor 3 is replaced with nitrogen 5 times before the reaction, adjust the rotation speed of the stirring paddle in the reactor to 100rpm, raise the temperature of the reactor to 25°C, and adjust the system pressure to 0.1MPaG, then control the first flowmeter 2 and the second Two flow meters 11, slowly drop material B and material A into the reactor simultaneously, the space velocity of material B and material A are both 14h -1 , ke...

Embodiment 2

[0088] A kind of preparation method of vitamin A acetate, process flow chart is as figure 1 As shown, the specific steps are as follows:

[0089] (1) Add 138g potassium carbonate solid powder in the first raw material tank 1, add 280mL water under stirring state, mix and obtain material B; Add 501.08g C15 phosphine salt, 156.2g C5 aldehyde in the second raw material tank 10, stir Add 2500mL mixed solvent (the volume ratio of water, methanol and n-hexane is 200:1:5) under the state, mix well to obtain material A, and nitrogen blanket for use;

[0090] (2) Reactor 3 is replaced with nitrogen 5 times before the reaction, adjust the rotating speed of the stirring paddle in the reactor to 300rpm, raise the temperature of the reactor to 25°C, and adjust the system pressure to 1.0MPaG, then control the first flowmeter 2 and the second Two flow meters 11, slowly drop material B and material A into the reactor simultaneously, the space velocity of material B and material A are both 10...

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Abstract

The invention provides a preparation method for vitamin A acetate. The preparation method comprises the following steps: carrying out an addition reaction on a C15 phosphonium salt and a C5 aldehyde in the presence of an alkali compound to generate an ylide salt; and subjecting the ylide to a decomposition reaction to obtain the vitamin A acetate, wherein the content of ylide in a reaction system in a reaction process is less than or equal to 0.06 mol/L. According to the preparation method, on the basis of a C15 + C5 Wittig reaction, the content of ylide in the reaction system in the reaction process is controlled, and the vitamin A acetate with high purity, high trans-isomerization selectivity and high yield is obtained. The preparation method is suitable for any-scale reaction and can be carried out in batches and conducted semi-continuously or completely continuously; and the obtained vitamin A acetate is low in chromatic value, good in oxidation resistance and thermal stability, low in deterioration rate, beneficial to long-term stable storage and very good in market competitiveness.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a preparation method of vitamin A acetate. Background technique [0002] Vitamin A acetate (VA acetate) is an important substance used in medicine, cosmetics, food, food supplements, and animal feed additives. It has the functions of maintaining visual function, maintaining the health of epithelial tissue cells, and promoting immunoglobulin synthesis. . Vitamin A acetate has the following three difficulties in storage and use: first, vitamin A acetate has extremely poor antioxidant properties and is easily oxidized and decomposed when exposed to air; second, vitamin A acetate has poor thermal stability , especially in hot summer, the problem of storage is more difficult; third, most commercially available vitamin A acetates are darker in color, with yellowish or reddish crystals, and the color will gradually deepen with time, and few manufacturers can Pro...

Claims

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Application Information

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IPC IPC(8): C07C403/12
CPCC07C403/12C07F9/657163C07C2601/16C07B2200/09Y02P20/55
Inventor 罗朝辉张涛吕英东林龙
Owner WANHUA CHEM GRP CO LTD
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