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A kind of synthetic method of bromoacetaldehyde diethyl acetal

A technology of bromoacetaldehyde diethyl acetal and a synthesis method, which is applied in chemical instruments and methods, preparation of carbon-based compounds, preparation of organic compounds, etc., can solve the problem of poor selectivity, difficult separation, and bromoacetaldehyde diethyl acetal products. Purity reduction and other problems, to achieve the effect of high purity and meet the requirements of high purity

Active Publication Date: 2015-10-28
HUANGGANG MEIFENG CHEM TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] 1) The process reported in the literature using vinyl acetate as a raw material has been used by a few domestic enterprises, but because the by-products in the alcoholysis process of this process have similar properties and are difficult to separate, the selectivity is not good and the yield is low
[0007] 2) The purity of bromoacetaldehyde diethyl acetal produced by the process of using vinyl acetate as raw material is less than 98.0%, and the product is easy to decompose and deteriorate during storage and transportation, making the bromoacetaldehyde diethyl acetal product pure. Further reduction, unable to meet the high purity (≥98.0%) requirements of domestic and foreign customers

Method used

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  • A kind of synthetic method of bromoacetaldehyde diethyl acetal
  • A kind of synthetic method of bromoacetaldehyde diethyl acetal
  • A kind of synthetic method of bromoacetaldehyde diethyl acetal

Examples

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Effect test

Embodiment 1

[0030] ① Catalytic bromination reaction: Stir and dissolve the raw materials paraldehyde 132kg, copper bromide 1.58kg, concentrated sulfuric acid 0.53L and anhydrous ethanol 858L, cool to below -5°C with an ice-salt bath, and then slowly drop into the reaction kettle Add 475kg of elemental bromine, control the reaction temperature below 0°C, finish the dropwise addition in 3 hours, and react at -5~0°C for 1 hour to obtain about 1200kg of ethanol solution of bromoacetaldehyde, which is directly used in the next step of acetalization without separation reaction;

[0031] ②Acetalization reaction: Put 150kg of anhydrous sodium sulfate into the ethanol solution of bromoacetaldehyde obtained in the previous step, heat up to 35°C, keep warm for 5 hours, then add 300L of ice water, stir for 15 minutes at room temperature, and add 180kg of sodium carbonate Neutralize the reaction solution so that the pH of the reaction solution is 6~7, stir, let stand to separate layers, separate the o...

Embodiment 2

[0034] ① Catalytic bromination reaction: Stir and dissolve the raw materials paraldehyde 132kg, cuprous bromide 1.4kg, concentrated sulfuric acid 0.4L and 800L absolute ethanol, cool to -5°C with an ice-salt bath, and then slowly drop into the reaction kettle Add 460kg of elemental bromine, control the reaction temperature below 0°C, finish the dropwise addition in 3 hours, and react at -5~0°C for 1 hour to obtain about 1150kg of ethanol solution of bromoacetaldehyde, which is directly used in the next step of acetalization without separation reaction.

[0035] ②Acetalization reaction: Add 120kg of anhydrous magnesium sulfate to the ethanol solution of bromoacetaldehyde obtained in the previous step, heat up to 40°C, keep the temperature for 5 hours, then add 250L of ice water to the reaction solution, and stir for 15 minutes at room temperature. Add 150kg of sodium carbonate to neutralize the reaction solution, make the pH of the reaction solution 6~7, stir, let stand to sep...

Embodiment 3

[0038] ① Catalytic bromination reaction: Stir and dissolve the raw materials paraldehyde 132kg, copper powder 2.0kg, concentrated sulfuric acid 1.0L, and absolute ethanol 1050L, cool to below -5°C with an ice-salt bath, and then slowly drop into the reaction kettle Add 520kg of elemental bromine, control the reaction temperature below 0°C, complete the dropwise addition in 4h, and react at -5~0°C for 1.5h to obtain about 1500kg of ethanol solution of bromoacetaldehyde, which is directly used in the next step of acetal without separation Chemical reaction;

[0039] ②Acetalization reaction: Put 225kg of anhydrous sodium sulfate into the ethanol solution of bromoacetaldehyde obtained in the previous step, heat up to 40°C, keep warm for 6 hours, then add 450L of ice water, stir for 20 minutes at room temperature, and add 200kg of sodium carbonate Neutralize the reaction solution to make the pH of the reaction solution 6~7, stir, let stand to separate layers, separate the organic l...

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Abstract

The invention discloses a synthesis method for bromoacetaldehyde diethyl acetal. The synthesis method for bromoacetaldehyde diethyl acetal is composed of the following process steps: (1) catalytic bromination reaction: stirring and dissolving raw materials, namely paracetaldehyde, a copper catalyst, concentrated sulphuric acid and absolute ethyl alcohol, cooling by an ice-salt bath, then slowly dropwise adding elementary-substance bromine in a reaction kettle, and reacting for 1-1.5 hours at minus 5-0 DEG C to obtain the ethanol solution of bromoacetaldehyde; (2) acetalation reaction: pouring an inorganic dehydrant in the ethanol solution of bromoacetaldehyde, which is obtained in the last step, heating to 35-40 DEG C, reacting for 5-6 hours while preserving heat, then adding ice water, reacting for 15-20 minutes, adding sodium carbonate to neutralize the reaction solution, stirring, standing to layer, separating out an organic layer, extracting a water layer by dichloroethane twice, mixing organic phases, carrying out reduced pressure distillation to recover a solvent, then carrying out reduced pressure distillation, and collecting fractions at 65-68 DEG C to obtain high-purity bromoacetaldehyde diethyl acetal. The synthesis method for bromoacetaldehyde diethyl acetal disclosed by the invention is available in raw materials, few in reaction steps, low in cost, high in product purity, and stable in quality.

Description

technical field [0001] The invention relates to a method for synthesizing an organic intermediate, in particular to a method for synthesizing the main organic intermediate bromoacetaldehyde diethyl acetal for producing the antibacterial drug dirithromycin. Background technique [0002] Bromoacetaldehyde diethyl acetal is the main organic intermediate for the production of antibacterial drug dierythromycin, and it is also the intermediate of important fine chemicals such as methimazole (hyperthyroidism drug), methotrimidine, anticancer drugs, pesticides and liquid crystal materials body raw materials. It is mainly used as the export of pharmaceutical intermediates and the supply to some domestic related enterprises involved in the production of dirithromycin, which has a good market prospect. [0003] At present, there are few reports on the synthesis process of bromoacetaldehyde diethyl acetal both at home and abroad. Among them, U.S. Patent US2411826 and Japanese Patent J...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C41/56C07C43/313
CPCC07C41/56C07C45/00C07C43/313C07C47/14
Inventor 汪敦佳刘建军李小林殷国栋范玲徐文立魏先红郑静
Owner HUANGGANG MEIFENG CHEM TECH
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