Method for purifying coarse trichloroacetaldehyde

A chloral, first-class technology, applied in the separation/purification of carbonyl compounds, organic chemistry, etc., can solve the problems of large steam consumption and high sulfuric acid consumption, and achieve improved refining yield, reduced sulfuric acid consumption, and mixing temperature low effect

Inactive Publication Date: 2011-04-27
XIANGTAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this method, chloral is distilled twice, and the consumption of steam is large, and the consumption of sulfuric acid is high at the same time, and the consumption of sulfuric acid per ton of arginaldehyde is 800-1000kg.

Method used

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  • Method for purifying coarse trichloroacetaldehyde

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] In the first-stage microstructure mixer, 0.3 kg of dilute sulfuric acid with a mass fraction of 75% is dispersed into 1 kg of crude chloral with a mass fraction of 70% through a microporous membrane tube and mixed evenly at a mixing temperature of 80°C. The stratifier is divided into layers, the lower layer is chloral, and the upper layer is dilute sulfuric acid. The dilute sulfuric acid in the upper layer reclaims residual chloral therein by distillation in the recovery kettle. In the secondary microstructure mixer, 0.2 kg of concentrated sulfuric acid with a mass fraction of 93% is dispersed into the chloral separated from the primary stratifier through the microporous membrane tube and mixed evenly. The mixing temperature is 95 ° C. After the two-stage stratifier is stratified, the upper layer separates a chloral layer containing a small amount of sulfuric acid, and the lower layer is a sulfuric acid layer. In the three-stage microstructure mixer, 0.1 kg of concentr...

Embodiment 2

[0019] In the first-stage microstructure mixer, 3kg of dilute sulfuric acid with a mass fraction of 75% is dispersed into 10kg of crude chloral with a mass fraction of 65% through a microporous membrane plate and mixed evenly, and the mixing temperature is 90°C. The stratifier is divided into layers, the lower layer is chloral, and the upper layer is dilute sulfuric acid. The dilute sulfuric acid in the upper layer reclaims the residual chloral therein through the distillation still. In the secondary microstructure mixer, 2 kg of concentrated sulfuric acid with a mass fraction of 98% is dispersed into the chloral separated from the primary stratifier through a microporous membrane plate and mixed evenly. The mixing temperature is 90 ° C. After the stratifier is stratified, the upper layer separates a chloral layer containing a small amount of sulfuric acid, and the lower layer is a sulfuric acid layer. In the three-stage microstructure mixer, 2kg of concentrated sulfuric acid...

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Abstract

The invention discloses a method for purifying coarse trichloroacetaldehyde. The method comprises the following steps that: the coarse trichloroacetaldehyde is fully mixed with dilute sulphuric acid in a primary microstructure mixer; trichloroacetaldehyde obtained by a primary demixer is fully mixed with concentrated sulfuric acid in a secondary microstructure mixer; trichloroacetaldehyde obtained after being demixed by a secondary demixer is continuously and fully mixed with concentrated sulfuric acid in a third microstructure mixer; trichloroacetaldehyde containing a small amount of sulfuric acid obtained after being demixed by a third demixer is rectified to obtain anhydrous trichloroacetaldehyde; after sulfuric acid demixed by the secondary demixer and the third demixer is mixed, a part of sulfuric acid is used as the dilute sulphuric acid for the primary microstructure mixer, and the residual sulfuric acid is mixed with the sulfuric acid demixed by the primary microstructure mixer and the residual sulfuric acid of a refining distillation kettle to distill and recycle the residual trichloroacetaldehyde; and the recycled trichloroacetaldehyde is mixed with the trichloroacetaldehyde demixed by the primary demixer to enter the secondary microstructure mixer. By the method, the coarse trichloroacetaldehyde is purified, the consumption of steam and the sulfuric acid can be reduced, and the refining yield of the trichloroacetaldehyde is improved.

Description

technical field [0001] The invention relates to a method for purifying crude chloral. Background technique [0002] Chloral is an important intermediate in the production of pesticides and medicines. At present, acetaldehyde chlorination is mostly used in foreign countries to prepare chloral. Domestically, ethanol chlorination is used to prepare chloral, and water is added in the late stage of the reaction to convert the alcoholic chloral into hydrated chloral, while ethanol continues to be chlorinated into chloral. Because the boiling points of chloral and water are very close, the current method for purifying crude chloral includes azeotropic distillation, and the entrainer includes dichloroethane, benzene and other solvents. This method is difficult to remove impurities in the reaction product, and the rectification process consumes a large amount of energy. The method for purifying crude chloral in the domestic industrial production process is a two-step method: first...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C47/16C07C45/80
Inventor 罗和安艾秋红李诚黄荣辉吴剑刘平乐
Owner XIANGTAN UNIV
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