Production method for refining propofol by dynamic accumulative distillation

Abstract

The present invention discloses a preparation method for phenol by a dynamical cumulated rectify and refine. A liquid-storing point is arranged on the top of a rectifying tower; the liquid-storing point and the rectifying tower form a full-reluence condensing loop; the liquid storing point is provided with a material-out valve; the dynamical cumulated rectifying operation is to add the coarse phenol into the rectifying tower to be heated for full-reluence condensation; after the concentration of the liquid-storing point in the rectifying tower satisfies the requirement, the material-out valve is to be opened to be made with full-out operation. And then the material-out valve is closes to be made with the full-reluence condensation. The step is repeated; and then the content of the phenol in the components is detected by a TLC tracking and monitoring meter until the rectifying process finishes. So the phenol satisfying the quality standard can be obtained. The present invention can exert the separating efficiency for the rectifying tower in the best degrees. The present invention adopts the non- reluence and full-out technology, which can make the concentration grads for the material in the rectifying tower be transferred quickly and dynamically. The present invention can overcome the influence to the separating efficiency of liquid-keeping amount for filling material or tower plate in part of reluence technics. Besides, the present invention can also overcome the problem that the transiting components in the precise fractionation process is hard to be cut accurately.

Description

technical field [0001] The invention relates to the preparation of propofol, in particular to a production method of propofol through dynamic cumulative rectification. Background technique [0002] The chemical name of propofol is 2,6-diisopropylphenol. Propofol is currently the most ideal and excellent anesthetic drug for clinical application. Its molecular structural formula is as follows: [0003] [0004] Crude propofol is usually obtained by alkylation of phenol with propylene, as described in USP2,831,898. It is almost inevitable that some other by-products will be produced in this process, such as 2-isopropylphenol, 2,4-diisopropylphenol, 2,5-diisopropylphenol, 2,6-diisopropylphenol phenyl isopropyl ether, 2,4,6-triisopropylphenol, etc. These impurities are usually strictly limited in the pharmacopoeias of various countries. [0005] USP NO.5,175,376 proposes a low-temperature crystallization separation process for propofol. This process is based on the princip...

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Problems solved by technology

However, if the number of theoretical plates is too high, it will cause a series of engineering problems such as excessive liquid holdup of the rectification tower and poor operation stability. These factors make the traditional rectification separation very difficult.

[0007] According to the method introduced in USP5,705,039, obtaining more than 99.8% of propofol requires more than 50 to 60 theoretical plates, and the requirements can only be met through multi-column or single-column multiple rectification. cumbersome

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