Method for preparing 2,3-butanedione from paraformaldehyde

A technology of paraformaldehyde and diacetyl, applied in the preparation of heterocyclic compounds, organic chemistry, etc., can solve the problems of unavailable raw materials, high technical content requirements, difficult industrial application, etc., and achieve novel synthetic routes, simple process operation, The effect of easy access to raw materials

Inactive Publication Date: 2013-01-02
HUNAN NORMAL UNIVERSITY
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  • Claims
  • Application Information

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Problems solved by technology

At present, the methods for synthesizing 2,3-butanedione both at home and abroad mainly include: 1. Extraction method from natural products: the product safety of this method is high and meets environmental protection requirements, but due to lack of raw materials, the cost of the product is high and not Suitable for mass production; 2. Glucose fermentation method: Although the raw material glucose has a wide range of sources, it requires high technical content, requires specific strains and a large production scale, and the equipment investment is relatively large, which is difficult for industrial application
3. Methyl Ethyl Ketone Oxidation Method: Methyl Ethyl Ketone Oxidation Method is one of the methods used by domestic manufacturers to produce 2,3-butanedione. This method is mature, but the selectivity of 2,3-butanedione is poor
4. Air oxidation of isobutyraldehyde; silver-copper catalyzed air oxidation of butanediol. These methods have the problems of unavailable raw materials, high cost, environmental pollution and low yield of 2,3-butanedione
5. Butanone nitrite oxidation method is a commonly used method in industrial production at present, but due to the large amount of nitrite used, it is carcinogenic and seriously affects the health of workers, and a large amount of hydrochloric acid and sulfuric acid are used in the reaction process. Severe corrosion of equipment and pollution of the environment
[0004] Recently, we have applied for a patent (Chinese invention patent, application number: 200910310246.8) for preparing 2,3-butanedione by one-step method of paraldehyde. , 3-butanedione provides a simple and environmentally friendly method, but the yield of diacetyl still needs to be further improved

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  • Method for preparing 2,3-butanedione from paraformaldehyde

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 20g acetone, 3.448g paraformaldehyde, 0.004molHCl, 1g L-proline, join together in the self-generating pressure reactor (the pressure that produces as temperature rises), start stirring and slowly heat up, and the reaction temperature is controlled at 100 DEG C, reaction time 2 hours, naturally cooled after the reaction, analyzed by gas chromatography, the conversion rate of paraformaldehyde was 99%, and the selectivity of methyl vinyl ketone was 96.7%.

[0029] Using synthesized methyl vinyl ketone as raw material, adjust the pH of the solution to 8, add 0.1 g of titanium-silicon molecular sieve catalyst, slowly add 16.39 g of hydrogen peroxide dropwise in a water bath at 55°C, and react with sodium bisulfite after 3 hours Adjust the pH of the solution to 1, continue to increase the reaction temperature to 80° C., and react for 2 hours. Analyzed by gas chromatography, the conversion rate of methyl vinyl ketone is 94.7%, and the selectivity of diacetyl is 85%.

Embodiment 2

[0031] 20g of acetone, 3.448g of paraformaldehyde, 0.004molHCl, and 2g of L-proline were added together into the self-generating pressure reactor, the stirring was started and the temperature was raised slowly, the reaction temperature was controlled at 100°C, and the reaction time was 2 hours. Cooling, analysis by gas chromatography, the conversion rate of paraformaldehyde is 99%, and the selectivity is 97%.

[0032] Using synthesized methyl vinyl ketone as raw material, adjust the pH to 8, add 0.1 g of titanium-silicon molecular sieve catalyst, slowly add 16.39 g of hydrogen peroxide dropwise in a water bath at 55°C, and adjust with sodium bisulfite after reacting for 3 hours pH = 1 (sodium bisulfite is added as a reducing agent to adjust the pH value of the solution) excess hydrogen peroxide, and the temperature is raised to 80° C. for 2 hours to prepare diacetyl. The conversion rate of methyl vinyl ketone was 97%, and the selectivity of diacetyl was 83%.

Embodiment 3

[0034] Add 20g of acetone, 1.724g of paraformaldehyde, 0.002molHCl, and 0.5g of L-proline together into the self-generating pressure reactor, start stirring and slowly raise the temperature, the reaction temperature is controlled at 100°C, and the reaction time is 2 hours. Cool naturally, analyze with gas chromatography, the conversion rate of paraformaldehyde is 99%, selectivity 87%.

[0035] Using synthetic methyl vinyl ketone as raw material, adjust pH=8, add 0.1g of titanium-silicon molecular sieve catalyst, slowly add 7.35g of hydrogen peroxide dropwise in a water bath at 55°C, and adjust with sodium bisulfite after reacting for 3 hours pH = 1 and excess hydrogen peroxide was reduced, and the temperature was raised to 80° C. for 2 hours to prepare diacetyl. The conversion rate of methyl vinyl ketone was 93.5%, and the selectivity of diacetyl was 82%.

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Abstract

The invention discloses a method for preparing 2,3-butanedione from paraformaldehyde. The method comprises the following steps of: preparing methyl vinyl ketone in one step from paraformaldehyde and acetone which serve as raw materials and L-proline serving as a catalyst through a condensation reaction of aldehydes and ketone and a dehydration reaction; and preparing 1,2-epoxy butanone from the methyl vinyl ketone serving as a raw material, hydrogen peroxide serving as an oxidant and a titanium and silicon molecular sieve serving as a catalyst by a catalytic oxidation method, and adding sodium hydrogensulfite for heating, and performing pinacol rearrangement to prepare 2,3-butanedione. Compared with the conventional method for preparing the 2,3-butanedione, the method has the characteristics of low cost, environmental-friendliness, high conversion rate of the paraformaldehyde and selectivity of the 2,3-butanedione and the like, and provides an environmental-friendly synthetic method for the industrial production of the 2,3-butanedione.

Description

technical field [0001] The invention belongs to the technical field of fine chemicals and relates to a method for preparing 2,3-butanedione. Background technique [0002] 2,3-Butanedione, yellow oily liquid, naturally exists in milk, fennel and a variety of fermented foods, mainly used in butter, margarine, cheese, candy and wine flavoring agents, etc., and also used as a synthetic flavor And intermediates of other chemical products. At present, the methods for synthesizing 2,3-butanedione both at home and abroad mainly include: 1. Extraction method from natural products: the product safety of this method is high and meets environmental protection requirements, but due to lack of raw materials, the cost of the product is high and not Suitable for mass production; 2. Glucose fermentation method: Although raw material glucose has a wide range of sources, it requires high technical content, requires specific strains and a large production scale, and requires relatively large e...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C49/12C07C45/58
Inventor 谭蓉周全银董红陈益民
Owner HUNAN NORMAL UNIVERSITY
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