Improved synthesizing technique for beta-carotene

Abstract

The invention discloses a making method of beta-carotene through coupling reaction, which is characterized by the following: adopting 30% hydrogen dioxide solution to couple two molecular organic phosphors; saving cost effectively; reacting vitamin A derivant and triphenylphosphine to produce organic phosphine salt; coupling under hypochlorite to obtain the product with water and water dissolutionas organic solvent; avoiding explosive accident; improving reacting safety effectively.

Description

technical field [0001] The invention relates to the preparation of vitamins, in particular to a method for obtaining beta-carotene by coupling reaction. Background technique [0002] β-carotene is an important drug in the vitamin A class, and its market prospect is very good. The organic phosphonium salt obtained by the reaction of vitamin A alcohol or its derivatives with triphenylphosphine is an important intermediate for the preparation of β-carotene, which can be further prepared by Wittig condensation reaction with vitamin A aldehyde to prepare β-carotene (Joachim Buddrus , et al., USP.3,634,518, Process for Preparing Alkylidene Phosphoranes, [P] 1972; Badische Anlin & Soda-Fabrik Aktiengesellschaft, DE 974,890, Production of Compounds of the Axerophthylidene Series, [P] 1964). It is also possible to carry out the condensation reaction between two molecules of organic phosphonium salts to prepare β-carotene (Bernhard Schulz, et al., USP.4,105,855, Manufacture of Symmet...

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Problems solved by technology

[0005] In the method of Bernhard Schulz et al., the methanol-water solution of vitamin A triphenylphosphine salt is first prepared, and after extracting with n-heptane to remove low-polarity impurities, the methanol is first evaporated under reduced pressure below 30°C, and then 30% Hydrogen peroxide is used to carry out the coupling reaction between two molecules of organic phosphine salts. After the reaction is completed, first filter to obtain a mixture of crude product β-carotene and by-products, and then recrystallize or rinse the solid mixture to remove triphenoxyphosphine. There are following disadvantages in this reaction: the hydrogen peroxide price is more expensive, and the production cost is high; the concentration of hydrogen peroxide is 30%, and it is easy to decompose during the reaction to cause dangerous consequences such as explosion, and industrial production is very unsafe; organic solvent), in the post-reaction treatment process, triphenoxyphosphine is precipitated together with the crude product of β-carotene during filtration, and needs to be recrystallized or rinsed to remove triphenoxyphosphine in the crude product of β-carotene, which will reduce the β-carotene - the purity of carotene.

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