Batch distillation-adsorption coupling method dehydration technology of trichloroacetaldehyde hydrate

Abstract

The invention discloses a batch distillation-adsorption coupling method dehydration technology of trichloroacetaldehyde hydrate. The technology solves the problems of chemical reaction affection and device corrosion, caused by the water content of above 0.1% in conventional trichloroacetaldehyde hydrate dehydration methods. The technology comprises the following specific steps: heating trichloroacetaldehyde hydrate in a distillation condensation system to form a molten state, starting stirring, adding concentrated sulfuric acid, continuously performing heating distillation, collecting the obtained 97-99 DEG C fraction, carrying out static adsorption on the collected trichloroacetaldehyde through a supported solid water absorbent, and then performing filtering separation to obtain anhydroustrichloroacetaldehyde. The batch distillation-adsorption coupling method reduces the cost of the dehydration process of trichloroacetaldehyde hydrate, and makes the technology economical and environmentally friendly, the concentrated sulfuric acid and the solid adsorbent used in the process can be recycled and repeatedly used, and the moisture content of the anhydrous trichloroacetaldehyde is reduced to 100 ppm or below.

Description

technical field [0001] The invention relates to a dehydration method of trichloroacetaldehyde, in particular to the dehydration technology of hydrated trichloroacetaldehyde intermittent distillation-adsorption coupling method, which belongs to the technical field of dehydration of crystalline chemicals. [0002] technical background [0003] Chloral is an important chemical raw material and an important intermediate in the preparation of medicines, pesticides and other organic chemical products. At present, domestically, the ethanol chlorination method is mainly used to prepare chloral, and after the reaction is completed, water is added to convert alcoholic chloral into hydrated chloral. [0004] The dehydration method of reported chloral hydrate mainly contains: 1. tower type continuous dehydration technology (CN101215228A), hydrate chloral and vitriol oil enter respectively from packing tower or plate tower tower top and tower bottom, carry out rectification then Obtain a...

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Problems solved by technology

[0004] The dehydration method of reported chloral hydrate mainly contains: 1. tower type continuous dehydration technology (CN101215228A), hydrate chloral and vitriol oil enter respectively from packing tower or plate tower tower top and tower bottom, carry out rectification then Obtain anhydrous chloral, though this method can continuously produce anhydrous chloral, need consume a large amount of concentrated sulfuric acid in the dehydration process, and a large amount of waste acid that produces can't handle; 2. azeotropic method removes water (CN1539806A, CN1868993A), make mixed solution with chloral hydrate and benzene, then remove water by water separator with benzene azeotropic method, this method process is simple, but needs to use a large amount of poisonous entrainer benzene

The moisture content of the anhydrous chloral obtained by the existing dehydration technology is greater than 0.1%, which cannot satisfy many organic synthesis reactions using anhydrous chloral as raw material. When the moisture content is high, it not only affects the smooth progress of the reaction, but also It will cause corrosion and other effects on industrial equipment, so a batch distillation-adsorption coupling dehydration technology is invented to improve product quality and reduce product moisture content

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