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Synthetic method for preparing 3,5-dichloro-2-pentanone with ethyl acetoacetate

A technology of ethyl acetoacetate and a synthesis method, which is applied to the preparation of carboxylate, the preparation of carbon-based compounds, chemical instruments and methods, etc., can solve problems such as hidden safety hazards, complicated handling, flammability and explosion, and prevent reaction coking. , improve the reaction yield, reduce the effect of safety hazards

Active Publication Date: 2017-12-15
ANHUI COSTAR BIOCHEM CO LTD
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Problems solved by technology

[0005] In the above synthetic route, the starting material uses ethylene oxide, which is inflammable and explosive, and is not easy for long-distance transportation, so there are strong regional restrictions; replace the above route with γ-butyrolactone and ethyl acetate, although avoid using cyclo Oxyethane, but this route requires the use of catalyst metal sodium, which has strong reducing properties and reacts violently with water, which can cause hydrogen combustion or even explosion. Therefore, large-scale use in industry has great potential safety hazards; and in the above route, some steps Using a variety of solvents, the solvent recovery is complicated, the cost is high, and the yield of some steps is low, and the post-reaction treatment is complicated, which is obviously not suitable for industrial production

Method used

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  • Synthetic method for preparing 3,5-dichloro-2-pentanone with ethyl acetoacetate
  • Synthetic method for preparing 3,5-dichloro-2-pentanone with ethyl acetoacetate

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preparation example Construction

[0026] Above-mentioned synthetic method specifically comprises the following steps:

[0027] (1) Chlorination reaction of 1,2-dichloroethane: Add ethanol solution of sodium ethoxide and 1,2-dichloroethane to the reactor Ⅰ, lower the temperature, then add ethyl acetoacetate dropwise to control the rate of addition, Control the reaction temperature and monitor the reaction degree by gas chromatography. After the reaction is complete, concentrate under reduced pressure, wash with water and separate the liquid, and put the lower organic phase directly into the reactor II;

[0028] (2) Sulfonyl chloride chlorination reaction: cool down the reactor II, add sulfuryl chloride dropwise, the reaction temperature is controlled at 5-10°C, and the reaction degree is monitored by gas chromatography;

[0029] (3) Dilute acid hydrolysis decarboxylation reaction, atmospheric distillation: After the reaction is complete, add water, dilute hydrochloric acid, and tetraethylammonium chloride to re...

Embodiment 1

[0036] A kind of synthetic method of preparing 3,5-dichloro-2-pentanone by ethyl acetoacetate, specifically comprises the following steps:

[0037] Add 245g (3.6mol) of sodium ethylate and 1550mL of ethanol to the reactor I in sequence, stir and dissolve, add 445g (4.5mol) of 1,2-dichloroethane, cool down to 0±1°C, and then start adding acetyl Ethyl acetate 387g (3mol), the rate of addition is controlled, and the reaction temperature is kept between 0-5°C. Use gas chromatography to monitor the reaction degree. After the reaction is complete, concentrate under reduced pressure at 30-40°C; add 500g of water to the concentrated residue and stir for 30min, separate the liquid, and pour the water phase into the waste liquid bucket; add 200g of water to the organic phase and stir for 30min. Separate the liquid, and put the lower organic phase directly into the reactor II. Reactor II was cooled to 5±1°C, 445g (3.3mol) of sulfuryl chloride was added dropwise, the reaction temperature...

Embodiment 2

[0039] A kind of synthetic method of preparing 3,5-dichloro-2-pentanone by ethyl acetoacetate, specifically comprises the following steps:

[0040] Add 204g (3mol) of sodium ethylate and 1291mL of ethanol to the reactor I in sequence, stir and dissolve, add 445g (4.5mol) of 1,2-dichloroethane, cool down to 0±1°C, and then start adding ethyl acetoacetate dropwise 387g (3mol), the rate of addition is controlled, and the reaction temperature is kept between 0-5°C. Use gas chromatography to monitor the reaction degree. After the reaction is complete, concentrate under reduced pressure at 30-40°C; add 500g of water to the concentrated residue and stir for 30min, separate the liquids, and pour the water phase into the waste liquid bucket; add 200g of water to the organic phase and stir for 30min. Separate the liquid, and put the lower organic phase directly into the reactor II. Reactor II was cooled to 5±1°C, 445g (3.3mol) of sulfuryl chloride was added dropwise, the reaction tempe...

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Abstract

The invention provides a synthetic method for preparing 3,5-dichloro-2-pentanone with ethyl acetoacetate. The method comprises the following steps that ethyl acetoacetate, sodium ethoxide, ethyl alcohol and 1,2-dichloroethane serve as raw materials, a chlorination reaction is conducted, and after a sulfonyl chloride chlorination reaction and a diluted acid hydrolysis decarboxylation reaction are conducted, 3,5-dichloro-2-pentanone is obtained through atmospheric distillation. Accordingly, ethyl acetoacetate, 1,2-dichloroethane, sulfonyl chloride, diluted acid and the like serve as the raw materials, the raw materials are low in toxicity, low in price and easy to obtain, active metal sodium and an inflammable and explosive material ethylene oxide are not used, the potential safety hazard of industrial scale -up production is lowered, the process is simple, and the product purity and yield are high.

Description

technical field [0001] The invention relates to the field of synthesis, in particular to a synthesis method for preparing 3,5-dichloro-2-pentanone from ethyl acetoacetate. Background technique [0002] 3,5-Dichloro-2-pentanone is a very important intermediate in the synthesis of various pharmaceutical and pesticides (clomethiazole, prothioconazole, etc.). [0003] In literature reports, the synthetic route of 3,5-dichloro-2-pentanone is mainly as follows: [0004] [0005] In the above synthetic route, the starting material uses ethylene oxide, which is inflammable and explosive, and is not easy for long-distance transportation, so there are strong regional restrictions; replace the above route with γ-butyrolactone and ethyl acetate, although avoid using cyclo Oxyethane, but this route requires the use of catalyst metal sodium, which has strong reducing properties and reacts violently with water, which can cause hydrogen combustion or even explosion. Therefore, large-sca...

Claims

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Application Information

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IPC IPC(8): C07C49/16C07C45/67C07C67/30C07C67/307C07C69/72
CPCC07C45/676C07C67/30C07C67/307C07C69/72C07C49/16
Inventor 袁晓路温兰兰韦琛鸿胡其钊唐先龙陶宗文王锋
Owner ANHUI COSTAR BIOCHEM CO LTD
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