Continuous synthesis process of alpha-chloro-alpha-acetyl-gamma-butyrolactone

Abstract

The invention relates to the technical field of chemical product preparation, and especially relates to a continuous synthesis process of alpha-chloro-alpha-acetyl-gamma-butyrolactone. The method comprises the steps that: alpha-acetyl-gamma-butyrolactone, water, and sodium bicarbonate are added into a same mixer; stirring is started, such that the materials are sufficiently mixed, and a premix liquid is prepared; the premix liquid is added into a constant-pressure premix liquid dropping funnel; through dropping flow meter metering, the liquid enters the bottom of a reaction kettle; chlorine gas is metered, and enters the bottom of the reaction kettle; a reaction temperature is controlled, such that a chlorination reaction is carried out; overflow liquid in the reaction kettle enters a stratification device through a discharge pipe, and stratification is carried out; upper-layer water layer is recovered through a water layer pipe, and a lower-layer finished product is recovered through a finished product pipe. According to the alpha-chloro-alpha-acetyl-gamma-butyrolactone continuous synthesis process, continuous production is realized, chlorine gas utilization rate is improved, product yield is improved, reaction rate is improved, and production capacity is improved.

Description

technical field [0001] The invention relates to the technical field of preparation of chemical products, in particular to a continuous synthesis process of α-chloro-α-acetyl-γ-butyrolactone. Background technique [0002] α-Chloro-α-acetyl-γ-butyrolactone is one of the important steps in the organic synthesis of vitamin B1. At present, all domestic companies or enterprises adopt batch-type chlorination reaction: add a certain amount of α-acetyl-γ-butyrolactone, water, sodium bicarbonate, control the temperature not to exceed 20°C under stirring, and feed measured chlorine gas into the bottom of the kettle. After the reaction is completed, let the layers stand for more than 10 hours, and then proceed Separation, the supernatant is α-chloro-α-acetyl-γ-butyrolactone. The chlorination reaction process of α-acetyl-γ-butyrolactone is very mature, but it has the following disadvantages: the reaction time for chlorine passage is long, generally more than 10 hours; due to the small h...

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Problems solved by technology

The chlorination reaction process of α-acetyl-γ-butyrolactone is very mature, but it has the following disadvantages: the reaction time for chlorine passage is long, generally more than 10 hours; due to the small heat exchange area of ​​the reactor, the requirements for refrigerant Higher, otherwise the reaction temperature is difficult to be effectively controlled, and there may be overheating locally; the large cross-sectional area of ​​the reactor makes the distribution of chlorine gas uneven, resulting in excessive local chlorine gas concentration, resulting in more α-acetyl-γ-butyrolactone Chlorination is a side reaction, and the utilization rate of chlorine gas is low, and more chlorine gas is directly discharged. Generally, 0.615kg chlorine gas / kg α-acetyl-γ-butyrolactone is required; the product yield is relatively low, generally between 94% and 95%. space; the number of reactors required is large, and the production capacity is low, etc.

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